| Message ID | 1438089593-7696-2-git-send-email-tomeu.vizoso@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jul 28, 2015 at 8:19 AM, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote: > Delay matches of platform devices until late_initcall, when we are sure > that all built-in drivers have been registered already. This is needed > to prevent deferred probes because of some drivers not having registered > yet. > > The reason why only platform devices are delayed is that some other > devices are expected to be probed earlier than late_initcall, for > example, the system PNP driver needs to probe its devices in > fs_initcall. > > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> > --- > > Changes in v2: > - Move delay to platform.c > > drivers/base/platform.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index 063f0ab15259..fcf654678e27 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -33,6 +33,8 @@ > /* For automatically allocated device IDs */ > static DEFINE_IDA(platform_devid_ida); > > +static bool enable_matches; > + > struct device platform_bus = { > .init_name = "platform", > }; > @@ -839,6 +841,15 @@ static int platform_match(struct device *dev, struct device_driver *drv) > struct platform_device *pdev = to_platform_device(dev); > struct platform_driver *pdrv = to_platform_driver(drv); > > + /* > + * Delay matches of platform devices until late_initcall, when we are > + * sure that all built-in drivers have been registered already. This > + * is needed to prevent deferred probes because of some drivers > + * not having registered yet. > + */ > + if (!enable_matches) > + return false; > + Having this as a global makes me nervous. I think it would be better to be DT specific or per device some how. Perhaps use OF_POPULATED_BUS flag as an additional test. There could be non-DT platforms that rely on the initcall ordering and moving all probes to late_initcall could change the ordering. I'm not sure though. Rob
On 30 July 2015 at 05:20, Rob Herring <robherring2@gmail.com> wrote: > On Tue, Jul 28, 2015 at 8:19 AM, Tomeu Vizoso > <tomeu.vizoso@collabora.com> wrote: >> Delay matches of platform devices until late_initcall, when we are sure >> that all built-in drivers have been registered already. This is needed >> to prevent deferred probes because of some drivers not having registered >> yet. >> >> The reason why only platform devices are delayed is that some other >> devices are expected to be probed earlier than late_initcall, for >> example, the system PNP driver needs to probe its devices in >> fs_initcall. >> >> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> >> --- >> >> Changes in v2: >> - Move delay to platform.c >> >> drivers/base/platform.c | 28 ++++++++++++++++++++++++++++ >> 1 file changed, 28 insertions(+) >> >> diff --git a/drivers/base/platform.c b/drivers/base/platform.c >> index 063f0ab15259..fcf654678e27 100644 >> --- a/drivers/base/platform.c >> +++ b/drivers/base/platform.c >> @@ -33,6 +33,8 @@ >> /* For automatically allocated device IDs */ >> static DEFINE_IDA(platform_devid_ida); >> >> +static bool enable_matches; >> + >> struct device platform_bus = { >> .init_name = "platform", >> }; >> @@ -839,6 +841,15 @@ static int platform_match(struct device *dev, struct device_driver *drv) >> struct platform_device *pdev = to_platform_device(dev); >> struct platform_driver *pdrv = to_platform_driver(drv); >> >> + /* >> + * Delay matches of platform devices until late_initcall, when we are >> + * sure that all built-in drivers have been registered already. This >> + * is needed to prevent deferred probes because of some drivers >> + * not having registered yet. >> + */ >> + if (!enable_matches) >> + return false; >> + > > Having this as a global makes me nervous. I think it would be better > to be DT specific or per device some how. Perhaps use OF_POPULATED_BUS > flag as an additional test. I see no problem with restricting this to platform devices with an of_node (or a fwnode if we still want to address machines with ACPI). > There could be non-DT platforms that rely on the initcall ordering and > moving all probes to late_initcall could change the ordering. I'm not > sure though. Yeah, I'm not sure how much that could be a problem. Maybe if a non-platform device has a match and probes before a platform device that has been delayed and is a dependency of it. That could be a problem in platforms that don't do on-demand probing because of the lack of firmware data. Thanks, Tomeu > Rob > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 063f0ab15259..fcf654678e27 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -33,6 +33,8 @@ /* For automatically allocated device IDs */ static DEFINE_IDA(platform_devid_ida); +static bool enable_matches; + struct device platform_bus = { .init_name = "platform", }; @@ -839,6 +841,15 @@ static int platform_match(struct device *dev, struct device_driver *drv) struct platform_device *pdev = to_platform_device(dev); struct platform_driver *pdrv = to_platform_driver(drv); + /* + * Delay matches of platform devices until late_initcall, when we are + * sure that all built-in drivers have been registered already. This + * is needed to prevent deferred probes because of some drivers + * not having registered yet. + */ + if (!enable_matches) + return false; + /* When driver_override is set, only bind to the matching driver */ if (pdev->driver_override) return !strcmp(pdev->driver_override, drv->name); @@ -859,6 +870,23 @@ static int platform_match(struct device *dev, struct device_driver *drv) return (strcmp(pdev->name, drv->name) == 0); } +static int __probe_device(struct device *dev, void *data) +{ + device_initial_probe(dev); + + return 0; +} + +static int probe_delayed_matches_initcall(void) +{ + enable_matches = true; + + bus_for_each_dev(&platform_bus_type, NULL, NULL, __probe_device); + + return 0; +} +late_initcall(probe_delayed_matches_initcall); + #ifdef CONFIG_PM_SLEEP static int platform_legacy_suspend(struct device *dev, pm_message_t mesg)
Delay matches of platform devices until late_initcall, when we are sure that all built-in drivers have been registered already. This is needed to prevent deferred probes because of some drivers not having registered yet. The reason why only platform devices are delayed is that some other devices are expected to be probed earlier than late_initcall, for example, the system PNP driver needs to probe its devices in fs_initcall. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> --- Changes in v2: - Move delay to platform.c drivers/base/platform.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)