Re: [PATCH v2 0/6] Update last busy timestamp in Runtime PM autosuspend callbacks

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Mon, Jun 16, 2025 at 07:20:21PM +0000, Sakari Ailus wrote:
> On Mon, Jun 16, 2025 at 01:21:02PM +0200, Rafael J. Wysocki wrote:
> > On Mon, Jun 16, 2025 at 8:12 AM Sakari Ailus wrote:
> > >
> > > Folks,
> > >
> > > The original plan for adding pm_runtime_mark_last_busy() calls to
> > > functions dealing with Runtime PM autosuspend originally included a few
> > > intermediate steps of driver conversion, including the use of recently
> > > added __pm_runtime_put_autosuspend(). The review of the set converting the
> > > users first to __pm_runtime_put_autosuspend() concluded this wasn't
> > > necessary. See
> > > <URL:https://lore.kernel.org/all/20241004094101.113349-1-sakari.ailus@linux.intel.com/>.
> > >
> > > This set extends the inclusion of the pm_runtime_mark_last_busy() call to
> > > the _autosuspend() variants of the Runtime PM functions dealing with
> > > suspending devices, i.e. pm_runtime_put_autosuspend(),
> > > pm_runtime_put_sync_autosuspend(), pm_runtime_autosuspend() and
> > > pm_request_autosuspend(). This will introduce, for a brief amount of time,
> > > unnecessary calls to pm_runtime_mark_last_busy() but this wasn't seen as
> > > an issue. Also, all users of these functions, including those that did not
> > > call pm_runtime_mark_last_busy(), will now include that call. Presumably
> > > in the vast majority of the cases a missing call would have been a bug.
> > >
> > > Once this set is merged, I'll post further patches to remove the extra
> > > pm_runtime_mark_last_busy() calls. The current set of these patches is
> > > here
> > > <URL:https://git.kernel.org/pub/scm/linux/kernel/git/sailus/linux-next.git/log/?h=pm-direct-on-next>.
> > >
> > > It'd be best to have all merged within the same cycle.
> > >
> > > Rafael: any thoughts on the merging?
> > 
> > I'm going to queue this up for 6.17.
> 
> Thank you! :-)
> 
> > > Would an immutable branch on top of rc1 be an option?
> > 
> > I think so, but does anyone need it?
> 
> I guess it's not mandatory but we'll have now a lot of redundant calls to
> the pm_runtime_mark_last_busy(). It just doesn't look very elegant. In the
> end it's all up to what the maintainers prefer.

Those calls should be removed, but for the drivers I maintain, I don't
mind much if the removal is delayed until v6.18. Still, an immutable
branch based on v6.16-rc1 would speed up this work, and I think it's
worth it.

-- 
Regards,

Laurent Pinchart