On Tue, Dec 2, 2025 at 2:06 AM Bart Van Assche <bvanassche@acm.org> wrote:
>
> On 12/1/25 11:58 AM, Rafael J. Wysocki wrote:
> > So I've been testing the patch below for a few days and it will eliminate
> > the latter, but even after this patch runtime PM will be disabled in
> > device_suspend_late() and if the problem you are facing is still there
> > after this patch, it will need to dealt with at the driver level.
> >
> > Generally speaking, driver involvement is needed to make runtime PM and
> > system suspend/resume work together in the majority of cases.
>
> Thank you for having developed and shared this patch. Is the following
> quote from the Linux kernel documentation still correct with this patch
> applied or should an update for Documentation/power/runtime_pm.rst
> perhaps be included in this patch?
>
>   "The power management workqueue pm_wq in which bus types and device
> drivers can
>    put their PM-related work items.  It is strongly recommended that
> pm_wq be
>    used for queuing all work items related to runtime PM, because this
> allows
>    them to be synchronized with system-wide power transitions (suspend
> to RAM,
>    hibernation and resume from system sleep states).  pm_wq is declared in
>    include/linux/pm_runtime.h and defined in kernel/power/main.c."

It doesn't say what the synchronization mechanism is in particular and
some synchronization is still provided after this patch, via the
pm_runtime_barrier() in device_suspend(), for example.