| Message ID | 20210929000735.585237-2-saravanak@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix simple-bus issues with fw_devlink | expand |
On Wed, Sep 29, 2021 at 2:07 AM Saravana Kannan <saravanak@google.com> wrote: > fw_devlink could end up creating device links for bus only devices. > However, bus only devices don't get probed and can block probe() or > sync_state() [1] call backs of other devices. To avoid this, probe these > devices using the simple-pm-bus driver. > > However, there are instances of devices that are not simple buses (they get > probed by their specific drivers) that also list the "simple-bus" (or other > bus only compatible strings) in their compatible property to automatically > populate their child devices. We still want these devices to get probed by > their specific drivers. So, we make sure this driver only probes devices > that are only buses. > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > Signed-off-by: Saravana Kannan <saravanak@google.com> > Tested-by: Saravana Kannan <saravanak@google.com> > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Works fine on R-Car Gen/Gen3 (simple-bus), and SH-Mobile AG5 and R-Mobile APE6 (simple-pm-bus). Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert
On 21-09-28 17:07:33, Saravana Kannan wrote: > fw_devlink could end up creating device links for bus only devices. > However, bus only devices don't get probed and can block probe() or > sync_state() [1] call backs of other devices. To avoid this, probe these > devices using the simple-pm-bus driver. > > However, there are instances of devices that are not simple buses (they get > probed by their specific drivers) that also list the "simple-bus" (or other > bus only compatible strings) in their compatible property to automatically > populate their child devices. We still want these devices to get probed by > their specific drivers. So, we make sure this driver only probes devices > that are only buses. > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > Signed-off-by: Saravana Kannan <saravanak@google.com> > Tested-by: Saravana Kannan <saravanak@google.com> > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > 1 file changed, 39 insertions(+), 3 deletions(-) > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > index 01a3d0cd08ed..6b8d6257ed8a 100644 > --- a/drivers/bus/simple-pm-bus.c > +++ b/drivers/bus/simple-pm-bus.c > @@ -13,11 +13,36 @@ > #include <linux/platform_device.h> > #include <linux/pm_runtime.h> > > - > static int simple_pm_bus_probe(struct platform_device *pdev) > { > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > - struct device_node *np = pdev->dev.of_node; > + const struct device *dev = &pdev->dev; > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > + struct device_node *np = dev->of_node; > + const struct of_device_id *match; > + > + /* > + * Allow user to use driver_override to bind this driver to a > + * transparent bus device which has a different compatible string > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > + * of the simple-pm-bus tasks for these devices, so return early. > + */ > + if (pdev->driver_override) > + return 0; > + > + match = of_match_device(dev->driver->of_match_table, dev); > + /* > + * These are transparent bus devices (not simple-pm-bus matches) that > + * have their child nodes populated automatically. So, don't need to > + * do anything more. We only match with the device if this driver is > + * the most specific match because we don't want to incorrectly bind to > + * a device that has a more specific driver. > + */ > + if (match && match->data) { > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > + return 0; > + else > + return -ENODEV; > + } This change is breaking the expected behavior for the already existent simple-bus nodes. All the simple-bus compatibles should be replaced now to simple-pm-bus. In my case, on some i.MX8 platforms, without the devlink, the devices suspend sequence changes (and even breaks). To avoid breaking the already existent simple-bus nodes, maybe the logic should've been reversed: keep the simple-bus as is and add another compatible, IDK, something like simple-trasnparent-bus, or something. > > dev_dbg(&pdev->dev, "%s\n", __func__); > > @@ -31,14 +56,25 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > static int simple_pm_bus_remove(struct platform_device *pdev) > { > + const void *data = of_device_get_match_data(&pdev->dev); > + > + if (pdev->driver_override || data) > + return 0; > + > dev_dbg(&pdev->dev, "%s\n", __func__); > > pm_runtime_disable(&pdev->dev); > return 0; > } > > +#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ > + > static const struct of_device_id simple_pm_bus_of_match[] = { > { .compatible = "simple-pm-bus", }, > + { .compatible = "simple-bus", .data = ONLY_BUS }, > + { .compatible = "simple-mfd", .data = ONLY_BUS }, > + { .compatible = "isa", .data = ONLY_BUS }, > + { .compatible = "arm,amba-bus", .data = ONLY_BUS }, > { /* sentinel */ } > }; > MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match); > -- > 2.33.0.685.g46640cef36-goog >
On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@kernel.org> wrote: > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > fw_devlink could end up creating device links for bus only devices. > > However, bus only devices don't get probed and can block probe() or > > sync_state() [1] call backs of other devices. To avoid this, probe these > > devices using the simple-pm-bus driver. > > > > However, there are instances of devices that are not simple buses (they get > > probed by their specific drivers) that also list the "simple-bus" (or other > > bus only compatible strings) in their compatible property to automatically > > populate their child devices. We still want these devices to get probed by > > their specific drivers. So, we make sure this driver only probes devices > > that are only buses. > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > Tested-by: Saravana Kannan <saravanak@google.com> > > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > > --- > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > --- a/drivers/bus/simple-pm-bus.c > > +++ b/drivers/bus/simple-pm-bus.c > > @@ -13,11 +13,36 @@ > > #include <linux/platform_device.h> > > #include <linux/pm_runtime.h> > > > > - > > static int simple_pm_bus_probe(struct platform_device *pdev) > > { > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > - struct device_node *np = pdev->dev.of_node; > > + const struct device *dev = &pdev->dev; > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > + struct device_node *np = dev->of_node; > > + const struct of_device_id *match; > > + > > + /* > > + * Allow user to use driver_override to bind this driver to a > > + * transparent bus device which has a different compatible string > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > + * of the simple-pm-bus tasks for these devices, so return early. > > + */ > > + if (pdev->driver_override) > > + return 0; > > + > > + match = of_match_device(dev->driver->of_match_table, dev); > > + /* > > + * These are transparent bus devices (not simple-pm-bus matches) that > > + * have their child nodes populated automatically. So, don't need to > > + * do anything more. We only match with the device if this driver is > > + * the most specific match because we don't want to incorrectly bind to > > + * a device that has a more specific driver. > > + */ > > + if (match && match->data) { > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > + return 0; > > + else > > + return -ENODEV; > > + } > > This change is breaking the expected behavior for the already existent > simple-bus nodes. All the simple-bus compatibles should be replaced now > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > devlink, the devices suspend sequence changes (and even breaks). > > To avoid breaking the already existent simple-bus nodes, maybe the logic > should've been reversed: keep the simple-bus as is and add another > compatible, IDK, something like simple-trasnparent-bus, or something. The intent of this change IS to affect existing simple-bus nodes (but not in the way it's affecting you). But if it's breaking stuff, we obviously need to fix it. I have a hunch on what's going on in your case, but can you point me to the specific simple-bus node that's getting affected? I'm expecting it to be a simple-bus node that gets added AFTER this driver is registered at device_initcall (module_init gets converted to device_initcall). Also, can you try this hack patch to see if it helps your case? https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@mail.gmail.com/ I have some thoughts on how I could fix this, but I need to think about a few cases. -Saravana > > > > > dev_dbg(&pdev->dev, "%s\n", __func__); > > > > @@ -31,14 +56,25 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > > > static int simple_pm_bus_remove(struct platform_device *pdev) > > { > > + const void *data = of_device_get_match_data(&pdev->dev); > > + > > + if (pdev->driver_override || data) > > + return 0; > > + > > dev_dbg(&pdev->dev, "%s\n", __func__); > > > > pm_runtime_disable(&pdev->dev); > > return 0; > > } > > > > +#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ > > + > > static const struct of_device_id simple_pm_bus_of_match[] = { > > { .compatible = "simple-pm-bus", }, > > + { .compatible = "simple-bus", .data = ONLY_BUS }, > > + { .compatible = "simple-mfd", .data = ONLY_BUS }, > > + { .compatible = "isa", .data = ONLY_BUS }, > > + { .compatible = "arm,amba-bus", .data = ONLY_BUS }, > > { /* sentinel */ } > > }; > > MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match); > > -- > > 2.33.0.685.g46640cef36-goog > >
On Wed, Nov 10, 2021 at 12:24 PM Saravana Kannan <saravanak@google.com> wrote: > > On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@kernel.org> wrote: > > > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > > fw_devlink could end up creating device links for bus only devices. > > > However, bus only devices don't get probed and can block probe() or > > > sync_state() [1] call backs of other devices. To avoid this, probe these > > > devices using the simple-pm-bus driver. > > > > > > However, there are instances of devices that are not simple buses (they get > > > probed by their specific drivers) that also list the "simple-bus" (or other > > > bus only compatible strings) in their compatible property to automatically > > > populate their child devices. We still want these devices to get probed by > > > their specific drivers. So, we make sure this driver only probes devices > > > that are only buses. > > > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > > Tested-by: Saravana Kannan <saravanak@google.com> > > > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > > > --- > > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > > --- a/drivers/bus/simple-pm-bus.c > > > +++ b/drivers/bus/simple-pm-bus.c > > > @@ -13,11 +13,36 @@ > > > #include <linux/platform_device.h> > > > #include <linux/pm_runtime.h> > > > > > > - > > > static int simple_pm_bus_probe(struct platform_device *pdev) > > > { > > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > > - struct device_node *np = pdev->dev.of_node; > > > + const struct device *dev = &pdev->dev; > > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > > + struct device_node *np = dev->of_node; > > > + const struct of_device_id *match; > > > + > > > + /* > > > + * Allow user to use driver_override to bind this driver to a > > > + * transparent bus device which has a different compatible string > > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > > + * of the simple-pm-bus tasks for these devices, so return early. > > > + */ > > > + if (pdev->driver_override) > > > + return 0; > > > + > > > + match = of_match_device(dev->driver->of_match_table, dev); > > > + /* > > > + * These are transparent bus devices (not simple-pm-bus matches) that > > > + * have their child nodes populated automatically. So, don't need to > > > + * do anything more. We only match with the device if this driver is > > > + * the most specific match because we don't want to incorrectly bind to > > > + * a device that has a more specific driver. > > > + */ > > > + if (match && match->data) { > > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > > + return 0; > > > + else > > > + return -ENODEV; > > > + } > > > > This change is breaking the expected behavior for the already existent > > simple-bus nodes. All the simple-bus compatibles should be replaced now > > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > > devlink, the devices suspend sequence changes (and even breaks). > > > > To avoid breaking the already existent simple-bus nodes, maybe the logic > > should've been reversed: keep the simple-bus as is and add another > > compatible, IDK, something like simple-trasnparent-bus, or something. > > The intent of this change IS to affect existing simple-bus nodes (but > not in the way it's affecting you). But if it's breaking stuff, we > obviously need to fix it. > > I have a hunch on what's going on in your case, but can you point me > to the specific simple-bus node that's getting affected? I'm expecting > it to be a simple-bus node that gets added AFTER this driver is > registered at device_initcall (module_init gets converted to > device_initcall). > > Also, can you try this hack patch to see if it helps your case? > https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@mail.gmail.com/ > > I have some thoughts on how I could fix this, but I need to think > about a few cases. Hi Abel, Friendly reminder. -Saravana
* Saravana Kannan <saravanak@google.com> [211115 20:19]: > On Wed, Nov 10, 2021 at 12:24 PM Saravana Kannan <saravanak@google.com> wrote: > > > > On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@kernel.org> wrote: > > > > > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > > > fw_devlink could end up creating device links for bus only devices. > > > > However, bus only devices don't get probed and can block probe() or > > > > sync_state() [1] call backs of other devices. To avoid this, probe these > > > > devices using the simple-pm-bus driver. > > > > > > > > However, there are instances of devices that are not simple buses (they get > > > > probed by their specific drivers) that also list the "simple-bus" (or other > > > > bus only compatible strings) in their compatible property to automatically > > > > populate their child devices. We still want these devices to get probed by > > > > their specific drivers. So, we make sure this driver only probes devices > > > > that are only buses. ... > > > > > > This change is breaking the expected behavior for the already existent > > > simple-bus nodes. All the simple-bus compatibles should be replaced now > > > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > > > devlink, the devices suspend sequence changes (and even breaks). > > > > > > To avoid breaking the already existent simple-bus nodes, maybe the logic > > > should've been reversed: keep the simple-bus as is and add another > > > compatible, IDK, something like simple-trasnparent-bus, or something. > > > > The intent of this change IS to affect existing simple-bus nodes (but > > not in the way it's affecting you). But if it's breaking stuff, we > > obviously need to fix it. > > > > I have a hunch on what's going on in your case, but can you point me > > to the specific simple-bus node that's getting affected? I'm expecting > > it to be a simple-bus node that gets added AFTER this driver is > > registered at device_initcall (module_init gets converted to > > device_initcall). > > > > Also, can you try this hack patch to see if it helps your case? > > https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@mail.gmail.com/ > > > > I have some thoughts on how I could fix this, but I need to think > > about a few cases. Not sure if this is related.. Some drivers need to be updated from builtin_platform_driver_probe() to use builtin_platform_driver() when switching to simple-pm-bus because of deferred probe. See more info in commit e259c2926c01 ("PCI: pci-dra7xx: Prepare for deferred probe with module_platform_driver"). Regards, Tony
On 21-11-15 12:17:46, Saravana Kannan wrote: > On Wed, Nov 10, 2021 at 12:24 PM Saravana Kannan <saravanak@google.com> wrote: > > > > On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@kernel.org> wrote: > > > > > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > > > fw_devlink could end up creating device links for bus only devices. > > > > However, bus only devices don't get probed and can block probe() or > > > > sync_state() [1] call backs of other devices. To avoid this, probe these > > > > devices using the simple-pm-bus driver. > > > > > > > > However, there are instances of devices that are not simple buses (they get > > > > probed by their specific drivers) that also list the "simple-bus" (or other > > > > bus only compatible strings) in their compatible property to automatically > > > > populate their child devices. We still want these devices to get probed by > > > > their specific drivers. So, we make sure this driver only probes devices > > > > that are only buses. > > > > > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > > > Tested-by: Saravana Kannan <saravanak@google.com> > > > > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > > > > --- > > > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > > > --- a/drivers/bus/simple-pm-bus.c > > > > +++ b/drivers/bus/simple-pm-bus.c > > > > @@ -13,11 +13,36 @@ > > > > #include <linux/platform_device.h> > > > > #include <linux/pm_runtime.h> > > > > > > > > - > > > > static int simple_pm_bus_probe(struct platform_device *pdev) > > > > { > > > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > > > - struct device_node *np = pdev->dev.of_node; > > > > + const struct device *dev = &pdev->dev; > > > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > > > + struct device_node *np = dev->of_node; > > > > + const struct of_device_id *match; > > > > + > > > > + /* > > > > + * Allow user to use driver_override to bind this driver to a > > > > + * transparent bus device which has a different compatible string > > > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > > > + * of the simple-pm-bus tasks for these devices, so return early. > > > > + */ > > > > + if (pdev->driver_override) > > > > + return 0; > > > > + > > > > + match = of_match_device(dev->driver->of_match_table, dev); > > > > + /* > > > > + * These are transparent bus devices (not simple-pm-bus matches) that > > > > + * have their child nodes populated automatically. So, don't need to > > > > + * do anything more. We only match with the device if this driver is > > > > + * the most specific match because we don't want to incorrectly bind to > > > > + * a device that has a more specific driver. > > > > + */ > > > > + if (match && match->data) { > > > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > > > + return 0; > > > > + else > > > > + return -ENODEV; > > > > + } > > > > > > This change is breaking the expected behavior for the already existent > > > simple-bus nodes. All the simple-bus compatibles should be replaced now > > > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > > > devlink, the devices suspend sequence changes (and even breaks). > > > > > > To avoid breaking the already existent simple-bus nodes, maybe the logic > > > should've been reversed: keep the simple-bus as is and add another > > > compatible, IDK, something like simple-trasnparent-bus, or something. > > > > The intent of this change IS to affect existing simple-bus nodes (but > > not in the way it's affecting you). But if it's breaking stuff, we > > obviously need to fix it. > > > > I have a hunch on what's going on in your case, but can you point me > > to the specific simple-bus node that's getting affected? I'm expecting > > it to be a simple-bus node that gets added AFTER this driver is > > registered at device_initcall (module_init gets converted to > > device_initcall). > > Well, for now, I can't pinpoint exactly one specific dts node. My usecase is a little bit more complicated since it's only happening in conjunction with a local change in the imx-mu-irq driver in our local tree. Basically, the local change is forcing a suspend abort by calling pm_system_wake if there is an irq from SCU triggered after the suspend noirq imx-mu-irq driver callback has been called. If we replace all the simple-bus with simple-pm-bus, everything works fine. > > Also, can you try this hack patch to see if it helps your case? > > https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@mail.gmail.com/ > > Nope, it doesn't work with this patch either. And the funny thing is, even if I add the pm_runtime_enable to your patch like this: diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c index 6b8d6257ed8a..a13324fd700b 100644 --- a/drivers/bus/simple-pm-bus.c +++ b/drivers/bus/simple-pm-bus.c @@ -38,9 +38,11 @@ static int simple_pm_bus_probe(struct platform_device *pdev) * a device that has a more specific driver. */ if (match && match->data) { - if (of_property_match_string(np, "compatible", match->compatible) == 0) + if (of_property_match_string(np, "compatible", match->compatible) == 0) { + pm_runtime_enable(&pdev->dev); + of_platform_populate(np, NULL, lookup, &pdev->dev); return 0; - else + } else return -ENODEV; } I get the following warning: [ 1.009392] ------------[ cut here ]------------ [ 1.013681] Enabling runtime PM for inactive device (bus@5d000000) with active children [ 1.021721] WARNING: CPU: 3 PID: 1 at drivers/base/power/runtime.c:1439 pm_runtime_enable+0xc0/0x100 [ 1.030794] Modules linked in: [ 1.033837] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.15.0-04906-gc0a8c67532b6-dirty #226 [ 1.042175] Hardware name: Freescale i.MX8QXP MEK (DT) [ 1.047302] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 1.054248] pc : pm_runtime_enable+0xc0/0x100 [ 1.058594] lr : pm_runtime_enable+0xc0/0x100 [ 1.062938] sp : ffff800011e4bb60 [ 1.066237] x29: ffff800011e4bb60 x28: 0000000000000000 x27: ffff8000119204d0 [ 1.073361] x26: ffff8000119c1060 x25: ffff8000119c1078 x24: ffff80001190f0a0 [ 1.080484] x23: 0000000000000000 x22: 0000000000000000 x21: ffff0008006a00f4 [ 1.087608] x20: 0000000000000000 x19: ffff0008006a0010 x18: 0000000000000030 [ 1.094732] x17: 6974636120687469 x16: 7720293030303030 x15: 3064354073756228 [ 1.101856] x14: 2065636976656420 x13: ffff800011c21dc0 x12: 0000000000000246 [ 1.108981] x11: 00000000000000c2 x10: ffff800011c79dc0 x9 : 00000000fffff000 [ 1.116103] x8 : ffff800011c21dc0 x7 : ffff800011c79dc0 x6 : 0000000000000000 [ 1.123227] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 00000000ffffefff [ 1.130351] x2 : ffff800011c21d30 x1 : 6bf7c63081c63600 x0 : 0000000000000000 [ 1.137478] Call trace: [ 1.139910] pm_runtime_enable+0xc0/0x100 [ 1.143903] simple_pm_bus_probe+0x80/0xf0 [ 1.147986] platform_probe+0x6c/0xe0 [ 1.151637] really_probe.part.0+0x9c/0x310 [ 1.155805] __driver_probe_device+0x98/0x144 [ 1.160149] driver_probe_device+0xc8/0x15c [ 1.164319] __driver_attach+0xfc/0x190 [ 1.168141] bus_for_each_dev+0x70/0xc0 [ 1.171964] driver_attach+0x28/0x3c [ 1.175526] bus_add_driver+0x108/0x1f0 [ 1.179348] driver_register+0x7c/0x130 [ 1.183173] __platform_driver_register+0x2c/0x40 [ 1.187862] simple_pm_bus_driver_init+0x20/0x2c [ 1.192466] do_one_initcall+0x54/0x1bc [ 1.196289] kernel_init_freeable+0x210/0x294 [ 1.200633] kernel_init+0x28/0x130 [ 1.204110] ret_from_fork+0x10/0x20 [ 1.207678] ---[ end trace 719a02e69bfeb03f ]--- though it should be behaving exactly like in the case of simple-pm-bus. Maybe I'm missing something here. I'll keep digging. > > I have some thoughts on how I could fix this, but I need to think > > about a few cases. > > Hi Abel, > > Friendly reminder. > Sorry for the late reply. > -Saravana
On 21-11-16 15:59:11, Abel Vesa wrote: > On 21-11-15 12:17:46, Saravana Kannan wrote: > > On Wed, Nov 10, 2021 at 12:24 PM Saravana Kannan <saravanak@google.com> wrote: > > > > > > On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@kernel.org> wrote: > > > > > > > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > > > > fw_devlink could end up creating device links for bus only devices. > > > > > However, bus only devices don't get probed and can block probe() or > > > > > sync_state() [1] call backs of other devices. To avoid this, probe these > > > > > devices using the simple-pm-bus driver. > > > > > > > > > > However, there are instances of devices that are not simple buses (they get > > > > > probed by their specific drivers) that also list the "simple-bus" (or other > > > > > bus only compatible strings) in their compatible property to automatically > > > > > populate their child devices. We still want these devices to get probed by > > > > > their specific drivers. So, we make sure this driver only probes devices > > > > > that are only buses. > > > > > > > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > > > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > > > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > > > > Tested-by: Saravana Kannan <saravanak@google.com> > > > > > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > > > > > --- > > > > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > > > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > > > > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > > > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > > > > --- a/drivers/bus/simple-pm-bus.c > > > > > +++ b/drivers/bus/simple-pm-bus.c > > > > > @@ -13,11 +13,36 @@ > > > > > #include <linux/platform_device.h> > > > > > #include <linux/pm_runtime.h> > > > > > > > > > > - > > > > > static int simple_pm_bus_probe(struct platform_device *pdev) > > > > > { > > > > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > > > > - struct device_node *np = pdev->dev.of_node; > > > > > + const struct device *dev = &pdev->dev; > > > > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > > > > + struct device_node *np = dev->of_node; > > > > > + const struct of_device_id *match; > > > > > + > > > > > + /* > > > > > + * Allow user to use driver_override to bind this driver to a > > > > > + * transparent bus device which has a different compatible string > > > > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > > > > + * of the simple-pm-bus tasks for these devices, so return early. > > > > > + */ > > > > > + if (pdev->driver_override) > > > > > + return 0; > > > > > + > > > > > + match = of_match_device(dev->driver->of_match_table, dev); > > > > > + /* > > > > > + * These are transparent bus devices (not simple-pm-bus matches) that > > > > > + * have their child nodes populated automatically. So, don't need to > > > > > + * do anything more. We only match with the device if this driver is > > > > > + * the most specific match because we don't want to incorrectly bind to > > > > > + * a device that has a more specific driver. > > > > > + */ > > > > > + if (match && match->data) { > > > > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > > > > + return 0; > > > > > + else > > > > > + return -ENODEV; > > > > > + } > > > > > > > > This change is breaking the expected behavior for the already existent > > > > simple-bus nodes. All the simple-bus compatibles should be replaced now > > > > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > > > > devlink, the devices suspend sequence changes (and even breaks). > > > > > > > > To avoid breaking the already existent simple-bus nodes, maybe the logic > > > > should've been reversed: keep the simple-bus as is and add another > > > > compatible, IDK, something like simple-trasnparent-bus, or something. > > > > > > The intent of this change IS to affect existing simple-bus nodes (but > > > not in the way it's affecting you). But if it's breaking stuff, we > > > obviously need to fix it. > > > > > > I have a hunch on what's going on in your case, but can you point me > > > to the specific simple-bus node that's getting affected? I'm expecting > > > it to be a simple-bus node that gets added AFTER this driver is > > > registered at device_initcall (module_init gets converted to > > > device_initcall). > > > > > Well, for now, I can't pinpoint exactly one specific dts node. > My usecase is a little bit more complicated since it's only happening > in conjunction with a local change in the imx-mu-irq driver > in our local tree. Basically, the local change is forcing a suspend abort by > calling pm_system_wake if there is an irq from SCU triggered after the > suspend noirq imx-mu-irq driver callback has been called. > If we replace all the simple-bus with simple-pm-bus, everything works > fine. > > > > Also, can you try this hack patch to see if it helps your case? > > > https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@mail.gmail.com/ > > > > > Nope, it doesn't work with this patch either. > > And the funny thing is, even if I add the pm_runtime_enable to your patch > like this: > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > index 6b8d6257ed8a..a13324fd700b 100644 > --- a/drivers/bus/simple-pm-bus.c > +++ b/drivers/bus/simple-pm-bus.c > @@ -38,9 +38,11 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > * a device that has a more specific driver. > */ > if (match && match->data) { > - if (of_property_match_string(np, "compatible", match->compatible) == 0) > + if (of_property_match_string(np, "compatible", match->compatible) == 0) { > + pm_runtime_enable(&pdev->dev); > + of_platform_populate(np, NULL, lookup, &pdev->dev); > return 0; > - else > + } else > return -ENODEV; > } > > I get the following warning: > > [ 1.009392] ------------[ cut here ]------------ > [ 1.013681] Enabling runtime PM for inactive device (bus@5d000000) with active children > [ 1.021721] WARNING: CPU: 3 PID: 1 at drivers/base/power/runtime.c:1439 pm_runtime_enable+0xc0/0x100 > [ 1.030794] Modules linked in: > [ 1.033837] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.15.0-04906-gc0a8c67532b6-dirty #226 > [ 1.042175] Hardware name: Freescale i.MX8QXP MEK (DT) > [ 1.047302] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > [ 1.054248] pc : pm_runtime_enable+0xc0/0x100 > [ 1.058594] lr : pm_runtime_enable+0xc0/0x100 > [ 1.062938] sp : ffff800011e4bb60 > [ 1.066237] x29: ffff800011e4bb60 x28: 0000000000000000 x27: ffff8000119204d0 > [ 1.073361] x26: ffff8000119c1060 x25: ffff8000119c1078 x24: ffff80001190f0a0 > [ 1.080484] x23: 0000000000000000 x22: 0000000000000000 x21: ffff0008006a00f4 > [ 1.087608] x20: 0000000000000000 x19: ffff0008006a0010 x18: 0000000000000030 > [ 1.094732] x17: 6974636120687469 x16: 7720293030303030 x15: 3064354073756228 > [ 1.101856] x14: 2065636976656420 x13: ffff800011c21dc0 x12: 0000000000000246 > [ 1.108981] x11: 00000000000000c2 x10: ffff800011c79dc0 x9 : 00000000fffff000 > [ 1.116103] x8 : ffff800011c21dc0 x7 : ffff800011c79dc0 x6 : 0000000000000000 > [ 1.123227] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 00000000ffffefff > [ 1.130351] x2 : ffff800011c21d30 x1 : 6bf7c63081c63600 x0 : 0000000000000000 > [ 1.137478] Call trace: > [ 1.139910] pm_runtime_enable+0xc0/0x100 > [ 1.143903] simple_pm_bus_probe+0x80/0xf0 > [ 1.147986] platform_probe+0x6c/0xe0 > [ 1.151637] really_probe.part.0+0x9c/0x310 > [ 1.155805] __driver_probe_device+0x98/0x144 > [ 1.160149] driver_probe_device+0xc8/0x15c > [ 1.164319] __driver_attach+0xfc/0x190 > [ 1.168141] bus_for_each_dev+0x70/0xc0 > [ 1.171964] driver_attach+0x28/0x3c > [ 1.175526] bus_add_driver+0x108/0x1f0 > [ 1.179348] driver_register+0x7c/0x130 > [ 1.183173] __platform_driver_register+0x2c/0x40 > [ 1.187862] simple_pm_bus_driver_init+0x20/0x2c > [ 1.192466] do_one_initcall+0x54/0x1bc > [ 1.196289] kernel_init_freeable+0x210/0x294 > [ 1.200633] kernel_init+0x28/0x130 > [ 1.204110] ret_from_fork+0x10/0x20 > [ 1.207678] ---[ end trace 719a02e69bfeb03f ]--- > > though it should be behaving exactly like in the case of simple-pm-bus. > > Maybe I'm missing something here. > > I'll keep digging. > One more thing. So basically, your already upstream patch removes the devlinks for all the simple-bus nodes. By adding your hack patch, it also removes devlinks between subnodes of the simple-bus node. > > > I have some thoughts on how I could fix this, but I need to think > > > about a few cases. > > > > Hi Abel, > > > > Friendly reminder. > > > > Sorry for the late reply. > > > -Saravana
On 21-11-16 17:11:33, Abel Vesa wrote: > On 21-11-16 15:59:11, Abel Vesa wrote: > > On 21-11-15 12:17:46, Saravana Kannan wrote: > > > On Wed, Nov 10, 2021 at 12:24 PM Saravana Kannan <saravanak@google.com> wrote: > > > > > > > > On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@kernel.org> wrote: > > > > > > > > > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > > > > > fw_devlink could end up creating device links for bus only devices. > > > > > > However, bus only devices don't get probed and can block probe() or > > > > > > sync_state() [1] call backs of other devices. To avoid this, probe these > > > > > > devices using the simple-pm-bus driver. > > > > > > > > > > > > However, there are instances of devices that are not simple buses (they get > > > > > > probed by their specific drivers) that also list the "simple-bus" (or other > > > > > > bus only compatible strings) in their compatible property to automatically > > > > > > populate their child devices. We still want these devices to get probed by > > > > > > their specific drivers. So, we make sure this driver only probes devices > > > > > > that are only buses. > > > > > > > > > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > > > > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > > > > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > > > > > Tested-by: Saravana Kannan <saravanak@google.com> > > > > > > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > > > > > > --- > > > > > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > > > > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > > > > > > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > > > > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > > > > > --- a/drivers/bus/simple-pm-bus.c > > > > > > +++ b/drivers/bus/simple-pm-bus.c > > > > > > @@ -13,11 +13,36 @@ > > > > > > #include <linux/platform_device.h> > > > > > > #include <linux/pm_runtime.h> > > > > > > > > > > > > - > > > > > > static int simple_pm_bus_probe(struct platform_device *pdev) > > > > > > { > > > > > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > > > > > - struct device_node *np = pdev->dev.of_node; > > > > > > + const struct device *dev = &pdev->dev; > > > > > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > > > > > + struct device_node *np = dev->of_node; > > > > > > + const struct of_device_id *match; > > > > > > + > > > > > > + /* > > > > > > + * Allow user to use driver_override to bind this driver to a > > > > > > + * transparent bus device which has a different compatible string > > > > > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > > > > > + * of the simple-pm-bus tasks for these devices, so return early. > > > > > > + */ > > > > > > + if (pdev->driver_override) > > > > > > + return 0; > > > > > > + > > > > > > + match = of_match_device(dev->driver->of_match_table, dev); > > > > > > + /* > > > > > > + * These are transparent bus devices (not simple-pm-bus matches) that > > > > > > + * have their child nodes populated automatically. So, don't need to > > > > > > + * do anything more. We only match with the device if this driver is > > > > > > + * the most specific match because we don't want to incorrectly bind to > > > > > > + * a device that has a more specific driver. > > > > > > + */ > > > > > > + if (match && match->data) { > > > > > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > > > > > + return 0; > > > > > > + else > > > > > > + return -ENODEV; > > > > > > + } > > > > > > > > > > This change is breaking the expected behavior for the already existent > > > > > simple-bus nodes. All the simple-bus compatibles should be replaced now > > > > > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > > > > > devlink, the devices suspend sequence changes (and even breaks). > > > > > > > > > > To avoid breaking the already existent simple-bus nodes, maybe the logic > > > > > should've been reversed: keep the simple-bus as is and add another > > > > > compatible, IDK, something like simple-trasnparent-bus, or something. > > > > > > > > The intent of this change IS to affect existing simple-bus nodes (but > > > > not in the way it's affecting you). But if it's breaking stuff, we > > > > obviously need to fix it. > > > > > > > > I have a hunch on what's going on in your case, but can you point me > > > > to the specific simple-bus node that's getting affected? I'm expecting > > > > it to be a simple-bus node that gets added AFTER this driver is > > > > registered at device_initcall (module_init gets converted to > > > > device_initcall). > > > > > > > > Well, for now, I can't pinpoint exactly one specific dts node. > > My usecase is a little bit more complicated since it's only happening > > in conjunction with a local change in the imx-mu-irq driver > > in our local tree. Basically, the local change is forcing a suspend abort by > > calling pm_system_wake if there is an irq from SCU triggered after the > > suspend noirq imx-mu-irq driver callback has been called. > > If we replace all the simple-bus with simple-pm-bus, everything works > > fine. > > > > > > Also, can you try this hack patch to see if it helps your case? > > > > https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@mail.gmail.com/ > > > > > > > > Nope, it doesn't work with this patch either. > > > > And the funny thing is, even if I add the pm_runtime_enable to your patch > > like this: > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > index 6b8d6257ed8a..a13324fd700b 100644 > > --- a/drivers/bus/simple-pm-bus.c > > +++ b/drivers/bus/simple-pm-bus.c > > @@ -38,9 +38,11 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > * a device that has a more specific driver. > > */ > > if (match && match->data) { > > - if (of_property_match_string(np, "compatible", match->compatible) == 0) > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) { > > + pm_runtime_enable(&pdev->dev); > > + of_platform_populate(np, NULL, lookup, &pdev->dev); > > return 0; > > - else > > + } else > > return -ENODEV; > > } > > > > I get the following warning: > > > > [ 1.009392] ------------[ cut here ]------------ > > [ 1.013681] Enabling runtime PM for inactive device (bus@5d000000) with active children > > [ 1.021721] WARNING: CPU: 3 PID: 1 at drivers/base/power/runtime.c:1439 pm_runtime_enable+0xc0/0x100 > > [ 1.030794] Modules linked in: > > [ 1.033837] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.15.0-04906-gc0a8c67532b6-dirty #226 > > [ 1.042175] Hardware name: Freescale i.MX8QXP MEK (DT) > > [ 1.047302] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > [ 1.054248] pc : pm_runtime_enable+0xc0/0x100 > > [ 1.058594] lr : pm_runtime_enable+0xc0/0x100 > > [ 1.062938] sp : ffff800011e4bb60 > > [ 1.066237] x29: ffff800011e4bb60 x28: 0000000000000000 x27: ffff8000119204d0 > > [ 1.073361] x26: ffff8000119c1060 x25: ffff8000119c1078 x24: ffff80001190f0a0 > > [ 1.080484] x23: 0000000000000000 x22: 0000000000000000 x21: ffff0008006a00f4 > > [ 1.087608] x20: 0000000000000000 x19: ffff0008006a0010 x18: 0000000000000030 > > [ 1.094732] x17: 6974636120687469 x16: 7720293030303030 x15: 3064354073756228 > > [ 1.101856] x14: 2065636976656420 x13: ffff800011c21dc0 x12: 0000000000000246 > > [ 1.108981] x11: 00000000000000c2 x10: ffff800011c79dc0 x9 : 00000000fffff000 > > [ 1.116103] x8 : ffff800011c21dc0 x7 : ffff800011c79dc0 x6 : 0000000000000000 > > [ 1.123227] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 00000000ffffefff > > [ 1.130351] x2 : ffff800011c21d30 x1 : 6bf7c63081c63600 x0 : 0000000000000000 > > [ 1.137478] Call trace: > > [ 1.139910] pm_runtime_enable+0xc0/0x100 > > [ 1.143903] simple_pm_bus_probe+0x80/0xf0 > > [ 1.147986] platform_probe+0x6c/0xe0 > > [ 1.151637] really_probe.part.0+0x9c/0x310 > > [ 1.155805] __driver_probe_device+0x98/0x144 > > [ 1.160149] driver_probe_device+0xc8/0x15c > > [ 1.164319] __driver_attach+0xfc/0x190 > > [ 1.168141] bus_for_each_dev+0x70/0xc0 > > [ 1.171964] driver_attach+0x28/0x3c > > [ 1.175526] bus_add_driver+0x108/0x1f0 > > [ 1.179348] driver_register+0x7c/0x130 > > [ 1.183173] __platform_driver_register+0x2c/0x40 > > [ 1.187862] simple_pm_bus_driver_init+0x20/0x2c > > [ 1.192466] do_one_initcall+0x54/0x1bc > > [ 1.196289] kernel_init_freeable+0x210/0x294 > > [ 1.200633] kernel_init+0x28/0x130 > > [ 1.204110] ret_from_fork+0x10/0x20 > > [ 1.207678] ---[ end trace 719a02e69bfeb03f ]--- > > > > though it should be behaving exactly like in the case of simple-pm-bus. > > > > Maybe I'm missing something here. > > > > I'll keep digging. > > Looking at this, it seems the devlinks are actually dropped after being created: [ 36.993371] Hardware name: Freescale i.MX8QXP MEK (DT) [ 36.998498] Call trace: [ 37.000928] dump_backtrace+0x0/0x19c [ 37.004578] show_stack+0x1c/0x70 [ 37.007878] dump_stack_lvl+0x68/0x84 [ 37.011527] dump_stack+0x1c/0x38 [ 37.014826] __device_link_del+0x40/0xbc [ 37.018738] device_link_drop_managed+0x74/0x90 [ 37.023253] device_links_driver_bound+0x1b4/0x280 [ 37.028031] driver_bound+0x68/0xd0 [ 37.031509] really_probe.part.0+0x258/0x310 [ 37.035763] __driver_probe_device+0x98/0x144 [ 37.040107] driver_probe_device+0xc8/0x15c [ 37.044279] __driver_attach+0xfc/0x190 [ 37.048100] bus_for_each_dev+0x70/0xc0 [ 37.051924] driver_attach+0x28/0x3c [ 37.055484] bus_add_driver+0x108/0x1f0 [ 37.059306] driver_register+0x7c/0x130 [ 37.063131] __platform_driver_register+0x2c/0x40 [ 37.067820] simple_pm_bus_driver_init+0x20/0x2c [ 37.072424] do_one_initcall+0x54/0x1bc [ 37.076249] kernel_init_freeable+0x210/0x294 [ 37.080591] kernel_init+0x28/0x130 [ 37.084068] ret_from_fork+0x10/0x20 [ 37.087688] simple-pm-bus bus@56220000: Dropping the link to 5d090000.gpio [ 37.094501] device: 'platform:5d090000.gpio--platform:bus@56220000': device_unregister So, before your patch, the devlinks were not dropped because there was no driver to probe for the "simple-bus" compatible. And I think this tells us why your hack patch didn't solve the problem either. > > One more thing. > > So basically, your already upstream patch removes the devlinks for all the simple-bus > nodes. > > By adding your hack patch, it also removes devlinks between subnodes of the simple-bus > node. > > > > > I have some thoughts on how I could fix this, but I need to think > > > > about a few cases. > > > > > > Hi Abel, > > > > > > Friendly reminder. > > > > > > > Sorry for the late reply. > > > > > -Saravana
On Fri, Nov 19, 2021 at 8:17 AM Abel Vesa <abel.vesa@nxp.com> wrote: > > On 21-11-16 17:11:33, Abel Vesa wrote: > > On 21-11-16 15:59:11, Abel Vesa wrote: > > > On 21-11-15 12:17:46, Saravana Kannan wrote: > > > > On Wed, Nov 10, 2021 at 12:24 PM Saravana Kannan <saravanak@google.com> wrote: > > > > > > > > > > On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@kernel.org> wrote: > > > > > > > > > > > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > > > > > > fw_devlink could end up creating device links for bus only devices. > > > > > > > However, bus only devices don't get probed and can block probe() or > > > > > > > sync_state() [1] call backs of other devices. To avoid this, probe these > > > > > > > devices using the simple-pm-bus driver. > > > > > > > > > > > > > > However, there are instances of devices that are not simple buses (they get > > > > > > > probed by their specific drivers) that also list the "simple-bus" (or other > > > > > > > bus only compatible strings) in their compatible property to automatically > > > > > > > populate their child devices. We still want these devices to get probed by > > > > > > > their specific drivers. So, we make sure this driver only probes devices > > > > > > > that are only buses. > > > > > > > > > > > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > > > > > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > > > > > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > > > > > > Tested-by: Saravana Kannan <saravanak@google.com> > > > > > > > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > > > > > > > --- > > > > > > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > > > > > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > > > > > > > > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > > > > > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > > > > > > --- a/drivers/bus/simple-pm-bus.c > > > > > > > +++ b/drivers/bus/simple-pm-bus.c > > > > > > > @@ -13,11 +13,36 @@ > > > > > > > #include <linux/platform_device.h> > > > > > > > #include <linux/pm_runtime.h> > > > > > > > > > > > > > > - > > > > > > > static int simple_pm_bus_probe(struct platform_device *pdev) > > > > > > > { > > > > > > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > > > > > > - struct device_node *np = pdev->dev.of_node; > > > > > > > + const struct device *dev = &pdev->dev; > > > > > > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > > > > > > + struct device_node *np = dev->of_node; > > > > > > > + const struct of_device_id *match; > > > > > > > + > > > > > > > + /* > > > > > > > + * Allow user to use driver_override to bind this driver to a > > > > > > > + * transparent bus device which has a different compatible string > > > > > > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > > > > > > + * of the simple-pm-bus tasks for these devices, so return early. > > > > > > > + */ > > > > > > > + if (pdev->driver_override) > > > > > > > + return 0; > > > > > > > + > > > > > > > + match = of_match_device(dev->driver->of_match_table, dev); > > > > > > > + /* > > > > > > > + * These are transparent bus devices (not simple-pm-bus matches) that > > > > > > > + * have their child nodes populated automatically. So, don't need to > > > > > > > + * do anything more. We only match with the device if this driver is > > > > > > > + * the most specific match because we don't want to incorrectly bind to > > > > > > > + * a device that has a more specific driver. > > > > > > > + */ > > > > > > > + if (match && match->data) { > > > > > > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > > > > > > + return 0; > > > > > > > + else > > > > > > > + return -ENODEV; > > > > > > > + } > > > > > > > > > > > > This change is breaking the expected behavior for the already existent > > > > > > simple-bus nodes. All the simple-bus compatibles should be replaced now > > > > > > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > > > > > > devlink, the devices suspend sequence changes (and even breaks). > > > > > > > > > > > > To avoid breaking the already existent simple-bus nodes, maybe the logic > > > > > > should've been reversed: keep the simple-bus as is and add another > > > > > > compatible, IDK, something like simple-trasnparent-bus, or something. > > > > > > > > > > The intent of this change IS to affect existing simple-bus nodes (but > > > > > not in the way it's affecting you). But if it's breaking stuff, we > > > > > obviously need to fix it. > > > > > > > > > > I have a hunch on what's going on in your case, but can you point me > > > > > to the specific simple-bus node that's getting affected? I'm expecting > > > > > it to be a simple-bus node that gets added AFTER this driver is > > > > > registered at device_initcall (module_init gets converted to > > > > > device_initcall). > > > > > > > > > > > Well, for now, I can't pinpoint exactly one specific dts node. > > > My usecase is a little bit more complicated since it's only happening > > > in conjunction with a local change in the imx-mu-irq driver > > > in our local tree. Basically, the local change is forcing a suspend abort by > > > calling pm_system_wake if there is an irq from SCU triggered after the > > > suspend noirq imx-mu-irq driver callback has been called. > > > If we replace all the simple-bus with simple-pm-bus, everything works > > > fine. I assume the local change you are referring to is only a code change and not a DT change? If so, can you please point me to the DTS of the board you are hitting this issue on? Even without your local code change, this can give me useful info. Maybe also point me to one of the simple-bus DT nodes that you needed to convert to simple-pm-bus for things to work? Maybe if you can find the minimal set of DT nodes that need a simple-bus to simple-pm-bus change, that'd be helpful. > > > > > > > > Also, can you try this hack patch to see if it helps your case? > > > > > https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@mail.gmail.com/ > > > > > > > > > > > Nope, it doesn't work with this patch either. > > > > > > And the funny thing is, even if I add the pm_runtime_enable to your patch > > > like this: > > > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > > index 6b8d6257ed8a..a13324fd700b 100644 > > > --- a/drivers/bus/simple-pm-bus.c > > > +++ b/drivers/bus/simple-pm-bus.c > > > @@ -38,9 +38,11 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > > * a device that has a more specific driver. > > > */ > > > if (match && match->data) { > > > - if (of_property_match_string(np, "compatible", match->compatible) == 0) > > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) { > > > + pm_runtime_enable(&pdev->dev); > > > + of_platform_populate(np, NULL, lookup, &pdev->dev); > > > return 0; > > > - else > > > + } else > > > return -ENODEV; > > > } > > > > > > I get the following warning: > > > > > > [ 1.009392] ------------[ cut here ]------------ > > > [ 1.013681] Enabling runtime PM for inactive device (bus@5d000000) with active children > > > [ 1.021721] WARNING: CPU: 3 PID: 1 at drivers/base/power/runtime.c:1439 pm_runtime_enable+0xc0/0x100 > > > [ 1.030794] Modules linked in: > > > [ 1.033837] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.15.0-04906-gc0a8c67532b6-dirty #226 > > > [ 1.042175] Hardware name: Freescale i.MX8QXP MEK (DT) > > > [ 1.047302] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > > [ 1.054248] pc : pm_runtime_enable+0xc0/0x100 > > > [ 1.058594] lr : pm_runtime_enable+0xc0/0x100 > > > [ 1.062938] sp : ffff800011e4bb60 > > > [ 1.066237] x29: ffff800011e4bb60 x28: 0000000000000000 x27: ffff8000119204d0 > > > [ 1.073361] x26: ffff8000119c1060 x25: ffff8000119c1078 x24: ffff80001190f0a0 > > > [ 1.080484] x23: 0000000000000000 x22: 0000000000000000 x21: ffff0008006a00f4 > > > [ 1.087608] x20: 0000000000000000 x19: ffff0008006a0010 x18: 0000000000000030 > > > [ 1.094732] x17: 6974636120687469 x16: 7720293030303030 x15: 3064354073756228 > > > [ 1.101856] x14: 2065636976656420 x13: ffff800011c21dc0 x12: 0000000000000246 > > > [ 1.108981] x11: 00000000000000c2 x10: ffff800011c79dc0 x9 : 00000000fffff000 > > > [ 1.116103] x8 : ffff800011c21dc0 x7 : ffff800011c79dc0 x6 : 0000000000000000 > > > [ 1.123227] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 00000000ffffefff > > > [ 1.130351] x2 : ffff800011c21d30 x1 : 6bf7c63081c63600 x0 : 0000000000000000 > > > [ 1.137478] Call trace: > > > [ 1.139910] pm_runtime_enable+0xc0/0x100 > > > [ 1.143903] simple_pm_bus_probe+0x80/0xf0 > > > [ 1.147986] platform_probe+0x6c/0xe0 > > > [ 1.151637] really_probe.part.0+0x9c/0x310 > > > [ 1.155805] __driver_probe_device+0x98/0x144 > > > [ 1.160149] driver_probe_device+0xc8/0x15c > > > [ 1.164319] __driver_attach+0xfc/0x190 > > > [ 1.168141] bus_for_each_dev+0x70/0xc0 > > > [ 1.171964] driver_attach+0x28/0x3c > > > [ 1.175526] bus_add_driver+0x108/0x1f0 > > > [ 1.179348] driver_register+0x7c/0x130 > > > [ 1.183173] __platform_driver_register+0x2c/0x40 > > > [ 1.187862] simple_pm_bus_driver_init+0x20/0x2c > > > [ 1.192466] do_one_initcall+0x54/0x1bc > > > [ 1.196289] kernel_init_freeable+0x210/0x294 > > > [ 1.200633] kernel_init+0x28/0x130 > > > [ 1.204110] ret_from_fork+0x10/0x20 > > > [ 1.207678] ---[ end trace 719a02e69bfeb03f ]--- > > > > > > though it should be behaving exactly like in the case of simple-pm-bus. Well, you aren't doing the "if (np)" check. So, it's possible this is triggering for a device without a DT node and is causing this warning? > > > > > > Maybe I'm missing something here. > > > > > > I'll keep digging. > > > > > Looking at this, it seems the devlinks are actually dropped after being > created: Yeah, that's the point of the change -- to drop SYNC_STATE_ONLY device links from the simple-bus node to other suppliers. And going by the name of the link being dropped, I'm fairly certain it's a SYNC_STATE_ONLY device (I doubt the simple-bus node in this example has a gpio property). If this behavior is causing issues for you, then (ok, this is going to be convoluted statement, so I'll split it into smaller chunks): 1. Take the suppliers of all the simple-bus node without my upstream patch. 2. Only some of them would have a sync_state() implementation (each to check -- they'd have a state_synced file in their device folder). 3. One of your OTHER devices has a dependency on the list of suppliers devices in (1) to keep a resource on. So the presence of the SYNC_STATE_ONLY links was preventing a supplier from turning off and was proxying for the needs of another device. You basically have to narrow this down to a supplier and then narrow it down to a consumer to fix the driver. Also, considering the limiter set of sync_state() implementations in upstream, I'd guess the supplier is either an interconnect or a PSCI power domain. The fact that switching to simple-pm-bus also makes me fairly certain the supplier in question is a power domain. Sorry for the vague answers. Without the specific DTS file, I can't give a better answer. > > [ 36.993371] Hardware name: Freescale i.MX8QXP MEK (DT) > [ 36.998498] Call trace: > [ 37.000928] dump_backtrace+0x0/0x19c > [ 37.004578] show_stack+0x1c/0x70 > [ 37.007878] dump_stack_lvl+0x68/0x84 > [ 37.011527] dump_stack+0x1c/0x38 > [ 37.014826] __device_link_del+0x40/0xbc > [ 37.018738] device_link_drop_managed+0x74/0x90 > [ 37.023253] device_links_driver_bound+0x1b4/0x280 > [ 37.028031] driver_bound+0x68/0xd0 > [ 37.031509] really_probe.part.0+0x258/0x310 > [ 37.035763] __driver_probe_device+0x98/0x144 > [ 37.040107] driver_probe_device+0xc8/0x15c > [ 37.044279] __driver_attach+0xfc/0x190 > [ 37.048100] bus_for_each_dev+0x70/0xc0 > [ 37.051924] driver_attach+0x28/0x3c > [ 37.055484] bus_add_driver+0x108/0x1f0 > [ 37.059306] driver_register+0x7c/0x130 > [ 37.063131] __platform_driver_register+0x2c/0x40 > [ 37.067820] simple_pm_bus_driver_init+0x20/0x2c > [ 37.072424] do_one_initcall+0x54/0x1bc > [ 37.076249] kernel_init_freeable+0x210/0x294 > [ 37.080591] kernel_init+0x28/0x130 > [ 37.084068] ret_from_fork+0x10/0x20 > [ 37.087688] simple-pm-bus bus@56220000: Dropping the link to 5d090000.gpio > [ 37.094501] device: 'platform:5d090000.gpio--platform:bus@56220000': device_unregister > > So, before your patch, the devlinks were not dropped because there was > no driver to probe for the "simple-bus" compatible. > > And I think this tells us why your hack patch didn't solve the problem > either. The hack patch is meant to make sure device links of sub nodes don't get dropped when they shouldn't be. It's strange that you saw the hack pack was causing the dropping of device links of sub nodes when my upstream patch doesn't (according to your other email). But I'll leave this for later. -Saravana
Hi Saravana, Saravana Kannan <saravanak@google.com> writes: > fw_devlink could end up creating device links for bus only devices. > However, bus only devices don't get probed and can block probe() or > sync_state() [1] call backs of other devices. To avoid this, probe these > devices using the simple-pm-bus driver. > > However, there are instances of devices that are not simple buses (they get > probed by their specific drivers) that also list the "simple-bus" (or other > bus only compatible strings) in their compatible property to automatically > populate their child devices. We still want these devices to get probed by > their specific drivers. So, we make sure this driver only probes devices > that are only buses. > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > Signed-off-by: Saravana Kannan <saravanak@google.com> > Tested-by: Saravana Kannan <saravanak@google.com> > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> This patch landed in stable/linux-5.10.y as commit d5f13bbb5104 and it broke suspend/resume on at least one TI AM335x board I'm testing on: upstream dts: arch/arm/boot/dts/am335x-icev2.dts, upstream defconfig: arch/arm/configs/omap2plus_defconfig. Bisecting between vanilla v5.10 (good) and stable/linux-5.10.y (bad) pointed me to this patch, and I confirmed that reverting just this patch on top of stable/linux-5.10.y makes it work again. Also interesting, this same platform works fine on vanilla v5.15, which also includes this patch. That suggests that either 1) this patch should not have been backported to v5.10 stable or 2) there are some other dependencies that are missing in v5.10. Since vanilla v5.10 works fine, I'm leaning towards (1), but if you have any ideas for deps that need backporting, I'm happy to try. I haven't debugged exactly where it's hanging yet, but, enabling CONFIG_DEBUG_DRIVER=y, and suspending with "no_console_suspend" on the command line, the last line before it hangs is: [ 28.129966] simple-pm-bus ocp: noirq power domain suspend Any ideas? Kevin
On Mon, Jan 31, 2022 at 7:18 PM Kevin Hilman <khilman@baylibre.com> wrote: > > Hi Saravana, > > Saravana Kannan <saravanak@google.com> writes: > > > fw_devlink could end up creating device links for bus only devices. > > However, bus only devices don't get probed and can block probe() or > > sync_state() [1] call backs of other devices. To avoid this, probe these > > devices using the simple-pm-bus driver. > > > > However, there are instances of devices that are not simple buses (they get > > probed by their specific drivers) that also list the "simple-bus" (or other > > bus only compatible strings) in their compatible property to automatically > > populate their child devices. We still want these devices to get probed by > > their specific drivers. So, we make sure this driver only probes devices > > that are only buses. > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > Tested-by: Saravana Kannan <saravanak@google.com> > > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> > > This patch landed in stable/linux-5.10.y as commit d5f13bbb5104 and it > broke suspend/resume on at least one TI AM335x board I'm testing on: > upstream dts: arch/arm/boot/dts/am335x-icev2.dts, upstream defconfig: > arch/arm/configs/omap2plus_defconfig. > > Bisecting between vanilla v5.10 (good) and stable/linux-5.10.y (bad) > pointed me to this patch, and I confirmed that reverting just this patch > on top of stable/linux-5.10.y makes it work again. > > Also interesting, this same platform works fine on vanilla v5.15, which > also includes this patch. That suggests that either 1) this patch > should not have been backported to v5.10 stable or 2) there are some > other dependencies that are missing in v5.10. > > Since vanilla v5.10 works fine, I'm leaning towards (1), but if you have > any ideas for deps that need backporting, I'm happy to try. Oh wow! I didn't realize I made so many changes AFTER 5.10! Unless I'm doing something wrong with my git commands. $ git log v5.10..v5.15 --oneline -- drivers/of/property.c $ git log v5.10..v5.15 --oneline --author=saravanak -- drivers/base/ If you don't think I got my git command completely wrong, yeah, way too many patches are missing on 5.10. I'd go with the option of dropping this patch on 5.10. > I haven't debugged exactly where it's hanging yet, but, enabling > CONFIG_DEBUG_DRIVER=y, and suspending with "no_console_suspend" on the > command line, the last line before it hangs is: > > [ 28.129966] simple-pm-bus ocp: noirq power domain suspend > > Any ideas? I'd guess it's either a sync_state() happening too soon since some of the dependencies aren't tracked. Or some dependency cycle that'd be handled correctly if the rest of the patches were picked up. Yeah, a pretty broad/vague answer. -Saravana
Saravana Kannan <saravanak@google.com> writes: > On Mon, Jan 31, 2022 at 7:18 PM Kevin Hilman <khilman@baylibre.com> wrote: >> >> Hi Saravana, >> >> Saravana Kannan <saravanak@google.com> writes: >> >> > fw_devlink could end up creating device links for bus only devices. >> > However, bus only devices don't get probed and can block probe() or >> > sync_state() [1] call backs of other devices. To avoid this, probe these >> > devices using the simple-pm-bus driver. >> > >> > However, there are instances of devices that are not simple buses (they get >> > probed by their specific drivers) that also list the "simple-bus" (or other >> > bus only compatible strings) in their compatible property to automatically >> > populate their child devices. We still want these devices to get probed by >> > their specific drivers. So, we make sure this driver only probes devices >> > that are only buses. >> > >> > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ >> > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") >> > Signed-off-by: Saravana Kannan <saravanak@google.com> >> > Tested-by: Saravana Kannan <saravanak@google.com> >> > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> >> >> This patch landed in stable/linux-5.10.y as commit d5f13bbb5104 and it >> broke suspend/resume on at least one TI AM335x board I'm testing on: >> upstream dts: arch/arm/boot/dts/am335x-icev2.dts, upstream defconfig: >> arch/arm/configs/omap2plus_defconfig. >> >> Bisecting between vanilla v5.10 (good) and stable/linux-5.10.y (bad) >> pointed me to this patch, and I confirmed that reverting just this patch >> on top of stable/linux-5.10.y makes it work again. >> >> Also interesting, this same platform works fine on vanilla v5.15, which >> also includes this patch. That suggests that either 1) this patch >> should not have been backported to v5.10 stable or 2) there are some >> other dependencies that are missing in v5.10. >> >> Since vanilla v5.10 works fine, I'm leaning towards (1), but if you have >> any ideas for deps that need backporting, I'm happy to try. > > Oh wow! I didn't realize I made so many changes AFTER 5.10! Unless I'm > doing something wrong with my git commands. > $ git log v5.10..v5.15 --oneline -- drivers/of/property.c > $ git log v5.10..v5.15 --oneline --author=saravanak -- drivers/base/ > > If you don't think I got my git command completely wrong, yeah, way > too many patches are missing on 5.10. I'd go with the option of > dropping this patch on 5.10. I agree. Could you submit a revert for v5.10 stable? As the patch author, it's probably better if it comes from you. >> I haven't debugged exactly where it's hanging yet, but, enabling >> CONFIG_DEBUG_DRIVER=y, and suspending with "no_console_suspend" on the >> command line, the last line before it hangs is: >> >> [ 28.129966] simple-pm-bus ocp: noirq power domain suspend >> >> Any ideas? > > I'd guess it's either a sync_state() happening too soon since some of > the dependencies aren't tracked. Or some dependency cycle that'd be > handled correctly if the rest of the patches were picked up. Yeah, a > pretty broad/vague answer. Heh, yeah, and also suggests that there's other gotchas hiding in other dark corners, which also suggests that revert is the best path for v5.10. Thanks for the quick response, Kevin
Kevin Hilman <khilman@baylibre.com> writes: > Saravana Kannan <saravanak@google.com> writes: > >> On Mon, Jan 31, 2022 at 7:18 PM Kevin Hilman <khilman@baylibre.com> wrote: >>> >>> Hi Saravana, >>> >>> Saravana Kannan <saravanak@google.com> writes: >>> >>> > fw_devlink could end up creating device links for bus only devices. >>> > However, bus only devices don't get probed and can block probe() or >>> > sync_state() [1] call backs of other devices. To avoid this, probe these >>> > devices using the simple-pm-bus driver. >>> > >>> > However, there are instances of devices that are not simple buses (they get >>> > probed by their specific drivers) that also list the "simple-bus" (or other >>> > bus only compatible strings) in their compatible property to automatically >>> > populate their child devices. We still want these devices to get probed by >>> > their specific drivers. So, we make sure this driver only probes devices >>> > that are only buses. >>> > >>> > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ >>> > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") >>> > Signed-off-by: Saravana Kannan <saravanak@google.com> >>> > Tested-by: Saravana Kannan <saravanak@google.com> >>> > Tested-by: Ulf Hansson <ulf.hansson@linaro.org> >>> >>> This patch landed in stable/linux-5.10.y as commit d5f13bbb5104 and it >>> broke suspend/resume on at least one TI AM335x board I'm testing on: >>> upstream dts: arch/arm/boot/dts/am335x-icev2.dts, upstream defconfig: >>> arch/arm/configs/omap2plus_defconfig. >>> >>> Bisecting between vanilla v5.10 (good) and stable/linux-5.10.y (bad) >>> pointed me to this patch, and I confirmed that reverting just this patch >>> on top of stable/linux-5.10.y makes it work again. >>> >>> Also interesting, this same platform works fine on vanilla v5.15, which >>> also includes this patch. That suggests that either 1) this patch >>> should not have been backported to v5.10 stable or 2) there are some >>> other dependencies that are missing in v5.10. >>> >>> Since vanilla v5.10 works fine, I'm leaning towards (1), but if you have >>> any ideas for deps that need backporting, I'm happy to try. >> >> Oh wow! I didn't realize I made so many changes AFTER 5.10! Unless I'm >> doing something wrong with my git commands. >> $ git log v5.10..v5.15 --oneline -- drivers/of/property.c >> $ git log v5.10..v5.15 --oneline --author=saravanak -- drivers/base/ >> >> If you don't think I got my git command completely wrong, yeah, way >> too many patches are missing on 5.10. I'd go with the option of >> dropping this patch on 5.10. > > I agree. Could you submit a revert for v5.10 stable? As the patch > author, it's probably better if it comes from you. Nevermind, I'm impatient and submitted a revert to stable[1] :) Kevin [1] https://lore.kernel.org/stable/20220202195705.3598798-1-khilman@baylibre.com/
diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c index 01a3d0cd08ed..6b8d6257ed8a 100644 --- a/drivers/bus/simple-pm-bus.c +++ b/drivers/bus/simple-pm-bus.c @@ -13,11 +13,36 @@ #include <linux/platform_device.h> #include <linux/pm_runtime.h> - static int simple_pm_bus_probe(struct platform_device *pdev) { - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); - struct device_node *np = pdev->dev.of_node; + const struct device *dev = &pdev->dev; + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); + struct device_node *np = dev->of_node; + const struct of_device_id *match; + + /* + * Allow user to use driver_override to bind this driver to a + * transparent bus device which has a different compatible string + * that's not listed in simple_pm_bus_of_match. We don't want to do any + * of the simple-pm-bus tasks for these devices, so return early. + */ + if (pdev->driver_override) + return 0; + + match = of_match_device(dev->driver->of_match_table, dev); + /* + * These are transparent bus devices (not simple-pm-bus matches) that + * have their child nodes populated automatically. So, don't need to + * do anything more. We only match with the device if this driver is + * the most specific match because we don't want to incorrectly bind to + * a device that has a more specific driver. + */ + if (match && match->data) { + if (of_property_match_string(np, "compatible", match->compatible) == 0) + return 0; + else + return -ENODEV; + } dev_dbg(&pdev->dev, "%s\n", __func__); @@ -31,14 +56,25 @@ static int simple_pm_bus_probe(struct platform_device *pdev) static int simple_pm_bus_remove(struct platform_device *pdev) { + const void *data = of_device_get_match_data(&pdev->dev); + + if (pdev->driver_override || data) + return 0; + dev_dbg(&pdev->dev, "%s\n", __func__); pm_runtime_disable(&pdev->dev); return 0; } +#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ + static const struct of_device_id simple_pm_bus_of_match[] = { { .compatible = "simple-pm-bus", }, + { .compatible = "simple-bus", .data = ONLY_BUS }, + { .compatible = "simple-mfd", .data = ONLY_BUS }, + { .compatible = "isa", .data = ONLY_BUS }, + { .compatible = "arm,amba-bus", .data = ONLY_BUS }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);
fw_devlink could end up creating device links for bus only devices. However, bus only devices don't get probed and can block probe() or sync_state() [1] call backs of other devices. To avoid this, probe these devices using the simple-pm-bus driver. However, there are instances of devices that are not simple buses (they get probed by their specific drivers) that also list the "simple-bus" (or other bus only compatible strings) in their compatible property to automatically populate their child devices. We still want these devices to get probed by their specific drivers. So, we make sure this driver only probes devices that are only buses. [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") Signed-off-by: Saravana Kannan <saravanak@google.com> Tested-by: Saravana Kannan <saravanak@google.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> --- drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- 1 file changed, 39 insertions(+), 3 deletions(-)