Re: [PATCH v2 2/7] pm: runtime: Add pm_runtime_put_mark_busy_autosusp() helper

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

Hi Sakari,

On Mon, Nov 20, 2023 at 09:27:51AM +0000, Sakari Ailus wrote:
> On Sat, Nov 18, 2023 at 11:30:31PM +0200, Laurent Pinchart wrote:
> > On Sat, Nov 18, 2023 at 10:20:46PM +0100, Rafael J. Wysocki wrote:
> > > On Sat, Nov 18, 2023 at 6:49 PM Laurent Pinchart wrote:
> > > > On Fri, Nov 17, 2023 at 01:14:28PM +0200, Sakari Ailus wrote:
> > > > > Add pm_runtime_put_mark_busy_autosusp() helper function for users that
> > > > > wish to set the last_busy timestamp to current time and put the
> > > > > usage_count of the device and set the autosuspend timer.
> > > > >
> > > > > Essentially calling pm_runtime_suspend_mark_busy_autosusp() equal to
> > > > > calling first pm_runtime_mark_last_busy() and then
> > > > > pm_runtime_put_autosuspend().
> > > >
> > > > The vast majority if the pm_runtime_put_autosuspend() users call
> > > > pm_runtime_mark_last_busy() right before. Let's make the
> > > > pm_runtime_put_autosuspend() function do that by default, and add a
> > > > __pm_runtime_put_autosuspend() (name to be bikshedded) for the minority
> > > > of cases where updating the last busy timestamp isn't desired. We want
> > > > to simplify the API, not make it more complex.
> > > 
> > > I would also prefer it to be done this way if not too problematic.
> > 
> > I'm glad you agree :-) The change will probably be a bit painful, but I
> > think it's for the best. Sakari, please let me know if I can help.
> 
> I actually do prefer this approach, too.
> 
> There about 350 drivers using pm_runtime_autosuspend() currently. Around
> 150 uses pm_runtime_autosuspend() which is not preceded by
> pm_runtime_mark_last_busy(). Call-wise the numbers are ~ 1050 and ~ 330.
> 
> I checked some of what's left: most do still call both, but in a way that
> evades Coccinelle matching. Some omissions seem to remain.
> 
> Given that there are way more users that do also call
> pm_runtime_mark_last_busy(), I think I'll try to introduce
> __pm_runtime_put_autosuspend() and pm_runtime_put_autosuspend()
> documentation change first and then rename the callers that don't use
> pm_runtime_mark_last_busy().

And also drop pm_runtime_mark_last_busy() from the drivers that call
pm_runtime_put_autosuspend(), right ?

This sounds good to me. Thank you for working on this. Two RPM API
simplifications in a week, it feels like Christmas is coming :-)

-- 
Regards,

Laurent Pinchart