Re: [PATCH v2] PCI / PM: Allow runtime PM without callback functions

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wednesday, December 12, 2018 12:42:29 PM CET Jarkko Nikula wrote:
> Hi
> 
> On 10/25/18 4:57 PM, Rafael J. Wysocki wrote:
> > On Tue, Oct 23, 2018 at 1:46 PM Jarkko Nikula
> > <jarkko.nikula@xxxxxxxxxxxxxxx> wrote:
> >>
> >> Commit a9c8088c7988 ("i2c: i801: Don't restore config registers on
> >> runtime PM") nullified the runtime PM suspend/resume callback pointers
> >> while keeping the runtime PM enabled.
> >>
> >> This causes that SMBus PCI device stays in D0 power state and sysfs
> >> /sys/bus/pci/devices/[SMBus PCI ID]/power/runtime_status shows "error"
> >> when the runtime PM framework attempts to autosuspend the device. This
> >> is due PCI bus runtime PM which checks for driver runtime PM callbacks
> >> and returns with -ENOSYS if they are not set.
> >>
> >> Since i2c-i801.c don't need to do anything device specific beyond PCI
> >> device power state management Jean Delvare proposed if this can be fixed
> >> in the PCI subsystem core level rather than adding dummy runtime PM
> >> callback functions in the PCI drivers.
> >>
> >> Change the pci_pm_runtime_suspend()/pci_pm_runtime_resume() semantics so
> >> that they allow change the PCI device power state during runtime PM
> >> transitions even if no runtime PM callback functions are defined.
> >>
> >> This change fixes the runtime PM regression on i2c-i801.c.
> >>
> >> It is not obvious why the code had hard requirements for the runtime PM
> >> callbacks. Test has been here since the code was introduced by the
> >> commit 6cbf82148ff2 ("PCI PM: Run-time callbacks for PCI bus type").
> >>
> >> On the other hand similar change than this was done to generic runtime
> >> PM callbacks way back in the commit 05aa55dddb9e ("PM / Runtime: Lenient
> >> generic runtime pm callbacks").
> >>
> >> Fixes: a9c8088c7988 ("i2c: i801: Don't restore config registers on runtime PM")
> >> Reported-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> >> Cc: <stable@xxxxxxxxxxxxxxx> # 4.18+
> >> Signed-off-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
> > 
> > Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > 
> I guess this patch with Reviewed-by tags from Rafael and Jean got buried 
> under other list traffic as I don't find this from pci.git or linux-next?

I guess it might not be entirely clear who was expected to pick it up.





[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux