Re: [PATCH 02/13] drm: Discard pm_runtime_put_autosuspend() return values

["Maíra Canal" <mcanal@igalia.com>]

Hi Brian,

On 06/10/26 20:13, Brian Norris wrote:
> Several DRM drivers use or propagate the pm_runtime_put_autosuspend()
> return value, which is not particularly useful.
> 
> Returning an error code from pm_runtime_put_autosuspend() merely means
> that it has not queued up a timer or work item to check whether or not
> the device can be suspended and there are many perfectly valid
> situations in which that can happen, like after writing "on" to the
> device's runtime PM "control" attribute in sysfs for one example.
> 
> For this reason, modify these drivers to simply discard the
> pm_runtime_put_autosuspend() return value, and change the return type of
> v3d_pm_runtime_put() (whose return value is never used) to void.  Also
> drop the redundant pm_runtime_mark_last_busy() calls right before
> pm_runtime_put_autosuspend().
> 
> This will facilitate a planned change of the
> pm_runtime_put_autosuspend() return type to void in the future, similar
> to commit 3afd8df02433 ("PM: runtime: Change pm_runtime_put() return
> type to void").
> 
> Signed-off-by: Brian Norris <briannorris@chromium.org>

For V3D,

Reviewed-by: Maíra Canal <mcanal@igalia.com>

Best regards,
- Maíra

> ---
> This patch is independent of the rest of the series, except for the end
> (changing the return type). I expect it can be applied by individual
> maintainers, and we pick up the end once the dust is settled.
> 
>   drivers/gpu/drm/panel/panel-simple.c | 8 +-------
>   drivers/gpu/drm/tidss/tidss_drv.c    | 7 +------
>   drivers/gpu/drm/v3d/v3d_drv.h        | 4 ++--
>   3 files changed, 4 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index c95964ba25a9..193d1b2b0ba5 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -318,12 +318,7 @@ static int panel_simple_suspend(struct device *dev)
>   
>   static int panel_simple_unprepare(struct drm_panel *panel)
>   {
> -	int ret;
> -
> -	pm_runtime_mark_last_busy(panel->dev);
> -	ret = pm_runtime_put_autosuspend(panel->dev);
> -	if (ret < 0)
> -		return ret;
> +	pm_runtime_put_autosuspend(panel->dev);
>   
>   	return 0;
>   }
> @@ -389,7 +384,6 @@ static int panel_simple_get_modes(struct drm_panel *panel,
>   
>   		num += drm_edid_connector_add_modes(connector);
>   
> -		pm_runtime_mark_last_busy(panel->dev);
>   		pm_runtime_put_autosuspend(panel->dev);
>   	}
>   
> diff --git a/drivers/gpu/drm/tidss/tidss_drv.c b/drivers/gpu/drm/tidss/tidss_drv.c
> index 1c8cc18bc53c..44b0b009c29a 100644
> --- a/drivers/gpu/drm/tidss/tidss_drv.c
> +++ b/drivers/gpu/drm/tidss/tidss_drv.c
> @@ -40,12 +40,7 @@ int tidss_runtime_get(struct tidss_device *tidss)
>   
>   void tidss_runtime_put(struct tidss_device *tidss)
>   {
> -	int r;
> -
> -	pm_runtime_mark_last_busy(tidss->dev);
> -
> -	r = pm_runtime_put_autosuspend(tidss->dev);
> -	WARN_ON(r < 0);
> +	pm_runtime_put_autosuspend(tidss->dev);
>   }
>   
>   static int __maybe_unused tidss_pm_runtime_suspend(struct device *dev)
> diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
> index 29fa14be130b..eb002048ae9c 100644
> --- a/drivers/gpu/drm/v3d/v3d_drv.h
> +++ b/drivers/gpu/drm/v3d/v3d_drv.h
> @@ -669,9 +669,9 @@ static __always_inline int v3d_pm_runtime_get(struct v3d_dev *v3d)
>   	return pm_runtime_resume_and_get(v3d->drm.dev);
>   }
>   
> -static __always_inline int v3d_pm_runtime_put(struct v3d_dev *v3d)
> +static __always_inline void v3d_pm_runtime_put(struct v3d_dev *v3d)
>   {
> -	return pm_runtime_put_autosuspend(v3d->drm.dev);
> +	pm_runtime_put_autosuspend(v3d->drm.dev);
>   }
>   
>   /* v3d_sched.c */