Re: [PATCH] gpu: host1x: fix runtime PM reference leak on remove

[Guangshuo Li]

Hi Mikko,

Thanks for the review.

On Mon, 14 Sept 2026 at 13:39, Mikko Perttunen <mperttunen@xxxxxxxxxx> wrote:
>
> On Sunday, September 13, 2026 9:02 PM Guangshuo Li wrote:
> > host1x_probe() calls pm_runtime_resume_and_get() and intentionally keeps
> > the runtime PM usage reference for the lifetime of the driver because
> > host1x is not yet ready for dynamic runtime PM.
> >
> > The probe error path drops this reference with
> > pm_runtime_put_sync_suspend(), but the remove path only calls
> > pm_runtime_force_suspend().
> >
> > pm_runtime_force_suspend() disables runtime PM and invokes the runtime
> > suspend callback when necessary, but it does not decrement the runtime
> > PM usage counter. As a result, the reference acquired by
> > pm_runtime_resume_and_get() remains held after the driver is unbound.
> > Repeated bind and unbind cycles can therefore leave the runtime PM
> > usage counter increasingly unbalanced.
> >
> > Drop the usage reference with pm_runtime_put_sync_suspend() before
> > forcing the device into suspend during removal.
> >
> > This issue was found by manual code inspection.
> >
> > Fixes: 6b6776e2ab8a ("gpu: host1x: Add initial runtime PM and OPP support")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
> > ---
> >  drivers/gpu/host1x/dev.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
> > index d2c64728f804..bb6a1647e4db 100644
> > --- a/drivers/gpu/host1x/dev.c
> > +++ b/drivers/gpu/host1x/dev.c
> > @@ -729,6 +729,7 @@ static void host1x_remove(struct platform_device *pdev)
> >       host1x_unregister(host);
> >       host1x_debug_deinit(host);
> >
> > +     pm_runtime_put_sync_suspend(&pdev->dev);
> >       pm_runtime_force_suspend(&pdev->dev);
>
> After the pm_runtime_put_sync_suspend, the device should always be
> suspended, so I think we should also replace the call to
> pm_runtime_force_suspend with a pm_runtime_disable.
>
> Thank you!
> Mikko
>
> >
> >       host1x_intr_deinit(host);
> > --
> > 2.43.0
> >
> >
>
>
>
>
That makes sense.

I'll replace pm_runtime_force_suspend() with pm_runtime_disable()
after pm_runtime_put_sync_suspend() and send a v2.

Thanks,
Guangshuo