Re: [PATCH] drm/etnaviv: fix runtime PM cleanup during teardown

[Johan Hovold <johan@kernel.org>]

On Sat, Aug 08, 2026 at 08:14:34PM +0800, Guangshuo Li wrote:
> etnaviv_gpu_platform_probe() calls pm_runtime_use_autosuspend() and
> enables runtime PM before registering the component. If component_add()
> fails, the probe path returns without undoing the autosuspend setting
> or disabling runtime PM. The remove path also disables runtime PM
> without calling the matching pm_runtime_dont_use_autosuspend().
> 
> If the autosuspend delay is set to a negative value while autosuspend
> is enabled, the runtime PM core increments usage_count to prevent
> runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
> during teardown, this reference is not dropped and usage_count remains
> unbalanced.

As I've explained elsewhere, this is just misleading. There is no usage
count leak here as the count is balanced whenever the user re-enables
autosuspend through sysfs (by writing a non-negative timeout).

Drivers should clean up after themselves and disable autosuspend, but
this is more of a clean up than a fix and should not be backported.

You've sent upwards of 60 of these in the matter of a just a few days,
some which have even been picked up. Please send follow-ups (replies or
v2s) as soon as possible to prevent further of these from getting
merged.

> The documentation for pm_runtime_use_autosuspend() also notes that it
> is important to undo it with pm_runtime_dont_use_autosuspend() at
> driver exit time, unless runtime PM was initially enabled with
> devm_pm_runtime_enable().
> 
> Undo the autosuspend setting on both probe failure and device removal,
> and disable runtime PM on the component registration failure path.
> 
> This issue was found by manual code inspection.
> 
> Fixes: a8c21a5451d8 ("drm/etnaviv: add initial etnaviv DRM driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>

Johan