| Message ID | 20211125073733.74902-2-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | f3380cac0c0b3a6f49ab161e2a057c363962f48d |
| Headers | show |
| Series | thunderbolt: Improvements for PM and USB4 compatibility | expand |
On Thursday, November 25, 2021 8:37:28 AM CET Mika Westerberg wrote: > If protocol tunnels are already up when the driver is loaded, for > instance if the boot firmware implements connection manager of its own, > runtime PM reference count of the consumer devices behind the tunnel > might have been increased already before the device link is created but > the supplier device runtime PM reference count is not. This leads to a > situation where the supplier (the Thunderbolt driver) can runtime > suspend even if it should not because the corresponding protocol tunnel > needs to be up causing the devices to be removed from the corresponding > native bus. > > Prevent this from happening by making both sides of the link runtime PM > active briefly. The pm_runtime_put() for the consumer (PCIe > root/downstream port, xHCI) then allows it to runtime suspend again but > keeps the supplier runtime resumed the whole time it is runtime active. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Thanks! > --- > drivers/thunderbolt/acpi.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/thunderbolt/acpi.c b/drivers/thunderbolt/acpi.c > index b67e72d5644b..7c9597a33929 100644 > --- a/drivers/thunderbolt/acpi.c > +++ b/drivers/thunderbolt/acpi.c > @@ -7,6 +7,7 @@ > */ > > #include <linux/acpi.h> > +#include <linux/pm_runtime.h> > > #include "tb.h" > > @@ -74,8 +75,18 @@ static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data, > pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))) { > const struct device_link *link; > > + /* > + * Make them both active first to make sure the NHI does > + * not runtime suspend before the consumer. The > + * pm_runtime_put() below then allows the consumer to > + * runtime suspend again (which then allows NHI runtime > + * suspend too now that the device link is established). > + */ > + pm_runtime_get_sync(&pdev->dev); > + > link = device_link_add(&pdev->dev, &nhi->pdev->dev, > DL_FLAG_AUTOREMOVE_SUPPLIER | > + DL_FLAG_RPM_ACTIVE | > DL_FLAG_PM_RUNTIME); > if (link) { > dev_dbg(&nhi->pdev->dev, "created link from %s\n", > @@ -84,6 +95,8 @@ static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data, > dev_warn(&nhi->pdev->dev, "device link creation from %s failed\n", > dev_name(&pdev->dev)); > } > + > + pm_runtime_put(&pdev->dev); > } > > out_put: >
diff --git a/drivers/thunderbolt/acpi.c b/drivers/thunderbolt/acpi.c index b67e72d5644b..7c9597a33929 100644 --- a/drivers/thunderbolt/acpi.c +++ b/drivers/thunderbolt/acpi.c @@ -7,6 +7,7 @@ */ #include <linux/acpi.h> +#include <linux/pm_runtime.h> #include "tb.h" @@ -74,8 +75,18 @@ static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data, pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))) { const struct device_link *link; + /* + * Make them both active first to make sure the NHI does + * not runtime suspend before the consumer. The + * pm_runtime_put() below then allows the consumer to + * runtime suspend again (which then allows NHI runtime + * suspend too now that the device link is established). + */ + pm_runtime_get_sync(&pdev->dev); + link = device_link_add(&pdev->dev, &nhi->pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER | + DL_FLAG_RPM_ACTIVE | DL_FLAG_PM_RUNTIME); if (link) { dev_dbg(&nhi->pdev->dev, "created link from %s\n", @@ -84,6 +95,8 @@ static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data, dev_warn(&nhi->pdev->dev, "device link creation from %s failed\n", dev_name(&pdev->dev)); } + + pm_runtime_put(&pdev->dev); } out_put:
If protocol tunnels are already up when the driver is loaded, for instance if the boot firmware implements connection manager of its own, runtime PM reference count of the consumer devices behind the tunnel might have been increased already before the device link is created but the supplier device runtime PM reference count is not. This leads to a situation where the supplier (the Thunderbolt driver) can runtime suspend even if it should not because the corresponding protocol tunnel needs to be up causing the devices to be removed from the corresponding native bus. Prevent this from happening by making both sides of the link runtime PM active briefly. The pm_runtime_put() for the consumer (PCIe root/downstream port, xHCI) then allows it to runtime suspend again but keeps the supplier runtime resumed the whole time it is runtime active. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- drivers/thunderbolt/acpi.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)