Re: [PATCH] drm/imx: dcss: fix autosuspend cleanup during teardown

Hi Guangshuo,

On Sat, Aug 08, 2026 at 08:23:54PM +0800, Guangshuo Li wrote:
> dcss_dev_create() calls pm_runtime_use_autosuspend(), but
> dcss_dev_destroy() does not call the matching
> pm_runtime_dont_use_autosuspend() before disabling runtime PM.
> 
> 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.
> 
> 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().
> 
> Add the missing pm_runtime_dont_use_autosuspend() call before
> disabling runtime PM during device teardown.
> 
> This issue was found by manual code inspection.
> 
> Fixes: 9021c317b770 ("drm/imx: Add initial support for DCSS on iMX8MQ")
> Cc: [email protected]
> Signed-off-by: Guangshuo Li <[email protected]>
> ---
>  drivers/gpu/drm/imx/dcss/dcss-dev.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/imx/dcss/dcss-dev.c b/drivers/gpu/drm/imx/dcss/dcss-dev.c
> index 7fd0c4c14205..51398852cdc2 100644
> --- a/drivers/gpu/drm/imx/dcss/dcss-dev.c
> +++ b/drivers/gpu/drm/imx/dcss/dcss-dev.c
> @@ -240,6 +240,7 @@ void dcss_dev_destroy(struct dcss_dev *dcss)
>  
>  	of_node_put(dcss->of_port);
>  
> +	pm_runtime_dont_use_autosuspend(dcss->dev);

This will call rpm_idle(), which will call dcss_dev_runtime_suspend(). So
you'll end up calling dcss_clocks_disable() twice... :/

>  	pm_runtime_disable(dcss->dev);
>  
>  	dcss_submodules_stop(dcss);
> -- 
> 2.43.0
> 

-- 
Thanks,
Laurentiu