Re: [PATCH] iio: proximity: srf04: fix runtime PM autosuspend cleanup

[Jonathan Cameron]

On Tue, 18 Aug 2026 09:14:15 +0200
Johan Hovold <johan@xxxxxxxxxx> wrote:

> On Fri, Aug 07, 2026 at 10:19:37PM +0800, Guangshuo Li wrote:
> > srf04_probe() calls pm_runtime_use_autosuspend() when the optional
> > power GPIO is present, but srf04_remove() does not call the matching
> > pm_runtime_dont_use_autosuspend() before disabling runtime PM.
> > 
> > The runtime PM documentation requires pm_runtime_use_autosuspend() to
> > be balanced with pm_runtime_dont_use_autosuspend() when the driver is
> > removed. Failing to do so can leave the autosuspend usage state
> > unbalanced and may result in a usage_count leak when the autosuspend
> > delay is negative.  
> 
> I believe the term "leak" here is misleading as the usage count would be
> dropped again when the user re-enables autosuspend through sysfs, right?

A user has no reason to do that under normal circumstances.
So whilst that might work it is rather non user friendly to the extent
I think I'd consider it a bug that should be fixed.  Backport or not
is a different question.

Jonathan


> 
> That said, drivers should clean up after themselves so disabling
> autosuspend is still the right to do. But it's more of a cleanup than a
> fix (and does not need to be backported).
> 
> Johan