Re: [PATCH 1/2] drm/panthor: Add PANTHOR_GROUP_PRIORITY_REALTIME group priority

[Mihail Atanassov <mihail.atanassov@arm.com>]

Hi Mary,

On 05/09/2024 12:13, Mary Guillemard wrote:
> This adds a new value to drm_panthor_group_priority exposing the
> realtime priority to userspace.
> 
> This is required to implement NV_context_priority_realtime in Mesa.
> 
> Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
> ---
>   drivers/gpu/drm/panthor/panthor_drv.c   | 2 +-
>   drivers/gpu/drm/panthor/panthor_sched.c | 2 --
>   include/uapi/drm/panthor_drm.h          | 7 +++++++
>   3 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index 0caf9e9a8c45..7b1db2adcb4c 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -1041,7 +1041,7 @@ static int group_priority_permit(struct drm_file *file,
>   				 u8 priority)
>   {
>   	/* Ensure that priority is valid */
> -	if (priority > PANTHOR_GROUP_PRIORITY_HIGH)
> +	if (priority > PANTHOR_GROUP_PRIORITY_REALTIME)
>   		return -EINVAL;
>   
>   	/* Medium priority and below are always allowed */
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 91a31b70c037..86908ada7335 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -137,8 +137,6 @@ enum panthor_csg_priority {
>   	 * non-real-time groups. When such a group becomes executable,
>   	 * it will evict the group with the lowest non-rt priority if
>   	 * there's no free group slot available.
> -	 *
> -	 * Currently not exposed to userspace.
>   	 */
>   	PANTHOR_CSG_PRIORITY_RT,
>   
> diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
> index 1fd8473548ac..011a555e4674 100644
> --- a/include/uapi/drm/panthor_drm.h
> +++ b/include/uapi/drm/panthor_drm.h
> @@ -720,6 +720,13 @@ enum drm_panthor_group_priority {
>   	 * Requires CAP_SYS_NICE or DRM_MASTER.
>   	 */
>   	PANTHOR_GROUP_PRIORITY_HIGH,
> +
> +	/**
> +	 * @PANTHOR_GROUP_PRIORITY_REALTIME: Realtime priority group.
> +	 *
> +	 * Requires CAP_SYS_NICE or DRM_MASTER.
> +	 */
> +	PANTHOR_GROUP_PRIORITY_REALTIME,

This is a uapi change, but doesn't have a corresponding driver version 
bump in the same patch. You also document the addition of this enum 
value in the next patch, which also is a tad wonky. If you reversed the 
order of the patches, they'd make more sense IMO.

>   };
>   
>   /**

-- 
Mihail Atanassov <mihail.atanassov@arm.com>