[PATCH v2 0/2] drm/panthor: Expose realtime group priority and allowed priorites to userspace

[PATCH v2 0/2] drm/panthor: Expose realtime group priority and allowed priorites to userspace

[Mary Guillemard]

This patch series adds support for realtime group priority and exposes
allowed priorities info with a new dev query.

Those changes are required to implement EGL_IMG_context_priority and
EGL_NV_context_priority_realtime extensions properly.

This patch series assumes that [1] is applied. (found in drm-misc-fixes)

The Mesa MR using this series is available here [2].

v2:
- Add Steven Price r-b on the first patch
- Remove drm_panthor_group_allow_priority_flags definition and document
  that allowed_mask is a bitmask of drm_panthor_group_priority on the
  second patch

[1]https://lore.kernel.org/all/20240903144955.144278-2-mary.guillemard@collabora.com/
[2]https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30991

Mary Guillemard (2):
  drm/panthor: Add PANTHOR_GROUP_PRIORITY_REALTIME group priority
  drm/panthor: Add DEV_QUERY_GROUP_PRIORITIES_INFO dev query

 drivers/gpu/drm/panthor/panthor_drv.c   | 61 +++++++++++++++++--------
 drivers/gpu/drm/panthor/panthor_sched.c |  2 -
 include/uapi/drm/panthor_drm.h          | 29 ++++++++++++
 3 files changed, 71 insertions(+), 21 deletions(-)

-- 
2.46.0

[PATCH v2 1/2] drm/panthor: Add PANTHOR_GROUP_PRIORITY_REALTIME group priority

[Mary Guillemard]

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.

v2:
- Add Steven Price r-b

Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.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,
 };
 
 /**
-- 
2.46.0

Re: [PATCH v2 1/2] drm/panthor: Add PANTHOR_GROUP_PRIORITY_REALTIME group priority

[Boris Brezillon]

On Thu,  5 Sep 2024 19:32:22 +0200
Mary Guillemard <mary.guillemard@collabora.com> 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.
> 
> v2:
> - Add Steven Price r-b
> 
> Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
> Reviewed-by: Steven Price <steven.price@arm.com>

Reviewed-by: Boris Brezillon <boris.brezillon@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,
>  };
>  
>  /**

[PATCH v2 2/2] drm/panthor: Add DEV_QUERY_GROUP_PRIORITIES_INFO dev query

[Mary Guillemard]

Expose allowed group priorities with a new device query.

This new uAPI will be used in Mesa to properly report what priorities a
user can use for EGL_IMG_context_priority.

Since this extends the uAPI and because userland needs a way to
advertise priorities accordingly, this also bumps the driver minor
version.

v2:
- Remove drm_panthor_group_allow_priority_flags definition
- Document that allowed_mask is a bitmask of drm_panthor_group_priority

Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
---
 drivers/gpu/drm/panthor/panthor_drv.c | 61 ++++++++++++++++++---------
 include/uapi/drm/panthor_drm.h        | 22 ++++++++++
 2 files changed, 64 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 7b1db2adcb4c..f85aa2d99f09 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -170,6 +170,7 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_gpu_info, tiler_present), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_csif_info, pad), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_timestamp_info, current_timestamp), \
+		 PANTHOR_UOBJ_DECL(struct drm_panthor_group_priorities_info, pad), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
@@ -777,11 +778,41 @@ static int panthor_query_timestamp_info(struct panthor_device *ptdev,
 	return 0;
 }
 
+static int group_priority_permit(struct drm_file *file,
+				 u8 priority)
+{
+	/* Ensure that priority is valid */
+	if (priority > PANTHOR_GROUP_PRIORITY_REALTIME)
+		return -EINVAL;
+
+	/* Medium priority and below are always allowed */
+	if (priority <= PANTHOR_GROUP_PRIORITY_MEDIUM)
+		return 0;
+
+	/* Higher priorities require CAP_SYS_NICE or DRM_MASTER */
+	if (capable(CAP_SYS_NICE) || drm_is_current_master(file))
+		return 0;
+
+	return -EACCES;
+}
+
+static void panthor_query_group_priorities_info(struct drm_file *file,
+						struct drm_panthor_group_priorities_info *arg)
+{
+	int prio;
+
+	for (prio = PANTHOR_GROUP_PRIORITY_REALTIME; prio >= 0; prio--) {
+		if (!group_priority_permit(file, prio))
+			arg->allowed_mask |= 1 << prio;
+	}
+}
+
 static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct drm_file *file)
 {
 	struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);
 	struct drm_panthor_dev_query *args = data;
 	struct drm_panthor_timestamp_info timestamp_info;
+	struct drm_panthor_group_priorities_info priorities_info;
 	int ret;
 
 	if (!args->pointer) {
@@ -798,6 +829,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
 			args->size = sizeof(timestamp_info);
 			return 0;
 
+		case DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO:
+			args->size = sizeof(priorities_info);
+			return 0;
+
 		default:
 			return -EINVAL;
 		}
@@ -818,6 +853,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
 
 		return PANTHOR_UOBJ_SET(args->pointer, args->size, timestamp_info);
 
+	case DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO:
+		panthor_query_group_priorities_info(file, &priorities_info);
+		return PANTHOR_UOBJ_SET(args->pointer, args->size, priorities_info);
+
 	default:
 		return -EINVAL;
 	}
@@ -1037,24 +1076,6 @@ static int panthor_ioctl_group_destroy(struct drm_device *ddev, void *data,
 	return panthor_group_destroy(pfile, args->group_handle);
 }
 
-static int group_priority_permit(struct drm_file *file,
-				 u8 priority)
-{
-	/* Ensure that priority is valid */
-	if (priority > PANTHOR_GROUP_PRIORITY_REALTIME)
-		return -EINVAL;
-
-	/* Medium priority and below are always allowed */
-	if (priority <= PANTHOR_GROUP_PRIORITY_MEDIUM)
-		return 0;
-
-	/* Higher priorities require CAP_SYS_NICE or DRM_MASTER */
-	if (capable(CAP_SYS_NICE) || drm_is_current_master(file))
-		return 0;
-
-	return -EACCES;
-}
-
 static int panthor_ioctl_group_create(struct drm_device *ddev, void *data,
 				      struct drm_file *file)
 {
@@ -1436,6 +1457,8 @@ static void panthor_debugfs_init(struct drm_minor *minor)
  * PanCSF driver version:
  * - 1.0 - initial interface
  * - 1.1 - adds DEV_QUERY_TIMESTAMP_INFO query
+ * - 1.2 - adds DEV_QUERY_GROUP_PRIORITIES_INFO query
+ *       - adds PANTHOR_GROUP_PRIORITY_REALTIME priority
  */
 static const struct drm_driver panthor_drm_driver = {
 	.driver_features = DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ |
@@ -1449,7 +1472,7 @@ static const struct drm_driver panthor_drm_driver = {
 	.desc = "Panthor DRM driver",
 	.date = "20230801",
 	.major = 1,
-	.minor = 1,
+	.minor = 2,
 
 	.gem_create_object = panthor_gem_create_object,
 	.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table,
diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
index 011a555e4674..87c9cb555dd1 100644
--- a/include/uapi/drm/panthor_drm.h
+++ b/include/uapi/drm/panthor_drm.h
@@ -263,6 +263,11 @@ enum drm_panthor_dev_query_type {
 
 	/** @DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO: Query timestamp information. */
 	DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO,
+
+	/**
+	 * @DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO: Query allowed group priorities information.
+	 */
+	DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO,
 };
 
 /**
@@ -399,6 +404,23 @@ struct drm_panthor_timestamp_info {
 	__u64 timestamp_offset;
 };
 
+/**
+ * struct drm_panthor_group_priorities_info - Group priorities information
+ *
+ * Structure grouping all queryable information relating to the allowed group priorities.
+ */
+struct drm_panthor_group_priorities_info {
+	/**
+	 * @allowed_mask: Bitmask of the allowed group priorities.
+	 *
+	 * Each bit represents a variant of the enum drm_panthor_group_priority.
+	 */
+	__u8 allowed_mask;
+
+	/** @pad: Padding fields, MBZ. */
+	__u8 pad[3];
+};
+
 /**
  * struct drm_panthor_dev_query - Arguments passed to DRM_PANTHOR_IOCTL_DEV_QUERY
  */
-- 
2.46.0

Re: [PATCH v2 2/2] drm/panthor: Add DEV_QUERY_GROUP_PRIORITIES_INFO dev query

[Boris Brezillon]

On Thu,  5 Sep 2024 19:32:23 +0200
Mary Guillemard <mary.guillemard@collabora.com> wrote:

> Expose allowed group priorities with a new device query.
> 
> This new uAPI will be used in Mesa to properly report what priorities a
> user can use for EGL_IMG_context_priority.
> 
> Since this extends the uAPI and because userland needs a way to
> advertise priorities accordingly, this also bumps the driver minor
> version.
> 
> v2:
> - Remove drm_panthor_group_allow_priority_flags definition
> - Document that allowed_mask is a bitmask of drm_panthor_group_priority
> 
> Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
> ---
>  drivers/gpu/drm/panthor/panthor_drv.c | 61 ++++++++++++++++++---------
>  include/uapi/drm/panthor_drm.h        | 22 ++++++++++
>  2 files changed, 64 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index 7b1db2adcb4c..f85aa2d99f09 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -170,6 +170,7 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_gpu_info, tiler_present), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_csif_info, pad), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_timestamp_info, current_timestamp), \
> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_group_priorities_info, pad), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
> @@ -777,11 +778,41 @@ static int panthor_query_timestamp_info(struct panthor_device *ptdev,
>  	return 0;
>  }
>  
> +static int group_priority_permit(struct drm_file *file,
> +				 u8 priority)
> +{
> +	/* Ensure that priority is valid */
> +	if (priority > PANTHOR_GROUP_PRIORITY_REALTIME)
> +		return -EINVAL;
> +
> +	/* Medium priority and below are always allowed */
> +	if (priority <= PANTHOR_GROUP_PRIORITY_MEDIUM)
> +		return 0;
> +
> +	/* Higher priorities require CAP_SYS_NICE or DRM_MASTER */
> +	if (capable(CAP_SYS_NICE) || drm_is_current_master(file))
> +		return 0;
> +
> +	return -EACCES;
> +}
> +
> +static void panthor_query_group_priorities_info(struct drm_file *file,
> +						struct drm_panthor_group_priorities_info *arg)
> +{
> +	int prio;
> +
> +	for (prio = PANTHOR_GROUP_PRIORITY_REALTIME; prio >= 0; prio--) {
> +		if (!group_priority_permit(file, prio))
> +			arg->allowed_mask |= 1 << prio;

nit: we have a BIT() macro for that ;-). Other than that, it looks good
to me.

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

Re: [PATCH v2 2/2] drm/panthor: Add DEV_QUERY_GROUP_PRIORITIES_INFO dev query

[Steven Price]

On 05/09/2024 18:32, Mary Guillemard wrote:
> Expose allowed group priorities with a new device query.
> 
> This new uAPI will be used in Mesa to properly report what priorities a
> user can use for EGL_IMG_context_priority.
> 
> Since this extends the uAPI and because userland needs a way to
> advertise priorities accordingly, this also bumps the driver minor
> version.
> 
> v2:
> - Remove drm_panthor_group_allow_priority_flags definition
> - Document that allowed_mask is a bitmask of drm_panthor_group_priority
> 
> Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>

With Boris' BIT() macro change:

Reviewed-by: Steven Price <steven.price@arm.com>

Thanks,
Steve

> ---
>  drivers/gpu/drm/panthor/panthor_drv.c | 61 ++++++++++++++++++---------
>  include/uapi/drm/panthor_drm.h        | 22 ++++++++++
>  2 files changed, 64 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index 7b1db2adcb4c..f85aa2d99f09 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -170,6 +170,7 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_gpu_info, tiler_present), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_csif_info, pad), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_timestamp_info, current_timestamp), \
> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_group_priorities_info, pad), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
> @@ -777,11 +778,41 @@ static int panthor_query_timestamp_info(struct panthor_device *ptdev,
>  	return 0;
>  }
>  
> +static int group_priority_permit(struct drm_file *file,
> +				 u8 priority)
> +{
> +	/* Ensure that priority is valid */
> +	if (priority > PANTHOR_GROUP_PRIORITY_REALTIME)
> +		return -EINVAL;
> +
> +	/* Medium priority and below are always allowed */
> +	if (priority <= PANTHOR_GROUP_PRIORITY_MEDIUM)
> +		return 0;
> +
> +	/* Higher priorities require CAP_SYS_NICE or DRM_MASTER */
> +	if (capable(CAP_SYS_NICE) || drm_is_current_master(file))
> +		return 0;
> +
> +	return -EACCES;
> +}
> +
> +static void panthor_query_group_priorities_info(struct drm_file *file,
> +						struct drm_panthor_group_priorities_info *arg)
> +{
> +	int prio;
> +
> +	for (prio = PANTHOR_GROUP_PRIORITY_REALTIME; prio >= 0; prio--) {
> +		if (!group_priority_permit(file, prio))
> +			arg->allowed_mask |= 1 << prio;
> +	}
> +}
> +
>  static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct drm_file *file)
>  {
>  	struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);
>  	struct drm_panthor_dev_query *args = data;
>  	struct drm_panthor_timestamp_info timestamp_info;
> +	struct drm_panthor_group_priorities_info priorities_info;
>  	int ret;
>  
>  	if (!args->pointer) {
> @@ -798,6 +829,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
>  			args->size = sizeof(timestamp_info);
>  			return 0;
>  
> +		case DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO:
> +			args->size = sizeof(priorities_info);
> +			return 0;
> +
>  		default:
>  			return -EINVAL;
>  		}
> @@ -818,6 +853,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
>  
>  		return PANTHOR_UOBJ_SET(args->pointer, args->size, timestamp_info);
>  
> +	case DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO:
> +		panthor_query_group_priorities_info(file, &priorities_info);
> +		return PANTHOR_UOBJ_SET(args->pointer, args->size, priorities_info);
> +
>  	default:
>  		return -EINVAL;
>  	}
> @@ -1037,24 +1076,6 @@ static int panthor_ioctl_group_destroy(struct drm_device *ddev, void *data,
>  	return panthor_group_destroy(pfile, args->group_handle);
>  }
>  
> -static int group_priority_permit(struct drm_file *file,
> -				 u8 priority)
> -{
> -	/* Ensure that priority is valid */
> -	if (priority > PANTHOR_GROUP_PRIORITY_REALTIME)
> -		return -EINVAL;
> -
> -	/* Medium priority and below are always allowed */
> -	if (priority <= PANTHOR_GROUP_PRIORITY_MEDIUM)
> -		return 0;
> -
> -	/* Higher priorities require CAP_SYS_NICE or DRM_MASTER */
> -	if (capable(CAP_SYS_NICE) || drm_is_current_master(file))
> -		return 0;
> -
> -	return -EACCES;
> -}
> -
>  static int panthor_ioctl_group_create(struct drm_device *ddev, void *data,
>  				      struct drm_file *file)
>  {
> @@ -1436,6 +1457,8 @@ static void panthor_debugfs_init(struct drm_minor *minor)
>   * PanCSF driver version:
>   * - 1.0 - initial interface
>   * - 1.1 - adds DEV_QUERY_TIMESTAMP_INFO query
> + * - 1.2 - adds DEV_QUERY_GROUP_PRIORITIES_INFO query
> + *       - adds PANTHOR_GROUP_PRIORITY_REALTIME priority
>   */
>  static const struct drm_driver panthor_drm_driver = {
>  	.driver_features = DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ |
> @@ -1449,7 +1472,7 @@ static const struct drm_driver panthor_drm_driver = {
>  	.desc = "Panthor DRM driver",
>  	.date = "20230801",
>  	.major = 1,
> -	.minor = 1,
> +	.minor = 2,
>  
>  	.gem_create_object = panthor_gem_create_object,
>  	.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table,
> diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
> index 011a555e4674..87c9cb555dd1 100644
> --- a/include/uapi/drm/panthor_drm.h
> +++ b/include/uapi/drm/panthor_drm.h
> @@ -263,6 +263,11 @@ enum drm_panthor_dev_query_type {
>  
>  	/** @DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO: Query timestamp information. */
>  	DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO,
> +
> +	/**
> +	 * @DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO: Query allowed group priorities information.
> +	 */
> +	DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO,
>  };
>  
>  /**
> @@ -399,6 +404,23 @@ struct drm_panthor_timestamp_info {
>  	__u64 timestamp_offset;
>  };
>  
> +/**
> + * struct drm_panthor_group_priorities_info - Group priorities information
> + *
> + * Structure grouping all queryable information relating to the allowed group priorities.
> + */
> +struct drm_panthor_group_priorities_info {
> +	/**
> +	 * @allowed_mask: Bitmask of the allowed group priorities.
> +	 *
> +	 * Each bit represents a variant of the enum drm_panthor_group_priority.
> +	 */
> +	__u8 allowed_mask;
> +
> +	/** @pad: Padding fields, MBZ. */
> +	__u8 pad[3];
> +};
> +
>  /**
>   * struct drm_panthor_dev_query - Arguments passed to DRM_PANTHOR_IOCTL_DEV_QUERY
>   */