> -----Original Message-----
> From: Murthy, Arun R <arun.r.murthy@xxxxxxxxx>
> Sent: Wednesday, February 5, 2025 3:57 PM
> To: dri-devel@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; intel-
> xe@xxxxxxxxxxxxxxxxxxxxx
> Cc: Borah, Chaitanya Kumar <chaitanya.kumar.borah@xxxxxxxxx>; Syrjala,
> Ville <ville.syrjala@xxxxxxxxx>; Murthy, Arun R <arun.r.murthy@xxxxxxxxx>
> Subject: [PATCH v4 1/3] drm/plane: Add new plane property
> IN_FORMATS_ASYNC
>
> There exists a property IN_FORMATS which exposes the plane supported
> modifiers/formats to the user. In some platforms when asynchronous flips are
> used all of modifiers/formats mentioned in IN_FORMATS are not supported.
> This patch adds a new plane property IN_FORMATS_ASYNC to expose the
> async flips supported modifiers/formats so that user can use this information
> ahead and done flips with unsupported formats/modifiers. This will save flips
s/done/do
s/flips/flip
> failures.
> Add a new function pointer similar to format_mod_supported specifically for
> asynchronous flips.
>
> v2: Remove async variable from drm_plane (Ville)
> v3: Add new function pointer for async (Ville)
>
> Signed-off-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_mode_config.c | 7 +++++++
> drivers/gpu/drm/drm_plane.c | 6 ++++++
> include/drm/drm_mode_config.h | 6 ++++++
> include/drm/drm_plane.h | 20 ++++++++++++++++++++
> 4 files changed, 39 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_mode_config.c
> b/drivers/gpu/drm/drm_mode_config.c
> index
> 8642a2fb25a90116dab975aa0ab6b51deafb4b96..dbbef20753f834a85ae9ded
> 748cff2b3f0e85043 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -388,6 +388,13 @@ static int
> drm_mode_create_standard_properties(struct drm_device *dev)
> return -ENOMEM;
> dev->mode_config.size_hints_property = prop;
>
> + prop = drm_property_create(dev,
> + DRM_MODE_PROP_IMMUTABLE |
> DRM_MODE_PROP_BLOB,
> + "IN_FORMATS_ASYNC", 0);
> + if (!prop)
> + return -ENOMEM;
> + dev->mode_config.async_modifiers_property = prop;
> +
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> index
> a28b22fdd7a41aca82d097d42237851da9a0a79b..416818e54ccffcf3d3aada27
> 23e96ce8ccf1dd97 100644
> --- a/drivers/gpu/drm/drm_plane.c
> +++ b/drivers/gpu/drm/drm_plane.c
> @@ -141,6 +141,12 @@
> * various bugs in this area with inconsistencies between the capability
> * flag and per-plane properties.
> *
> + * IN_FORMATS_ASYNC:
> + * Blob property which contains the set of buffer format and modifier
> + * pairs supported by this plane for asynchronous flips. The blob is a struct
> + * drm_format_modifier_blob. Without this property the plane doesn't
> + * support buffers with modifiers.
As pointed out in my previous comment we should remove this line or replace it with something like this
Without this property the plane supports all the format modifier pair listed by IN_FORMAT for asynchronous flips.
> Userspace cannot change this property.
> + *
> * SIZE_HINTS:
> * Blob property which contains the set of recommended plane size
> * which can used for simple "cursor like" use cases (eg. no scaling).
> diff --git a/include/drm/drm_mode_config.h
> b/include/drm/drm_mode_config.h index
> 271765e2e9f2da62aaf0d258828ef4196e14822e..0c116d6dfd277262b1a4c0f0
> 97fce2d719f43844 100644
> --- a/include/drm/drm_mode_config.h
> +++ b/include/drm/drm_mode_config.h
> @@ -936,6 +936,12 @@ struct drm_mode_config {
> */
> struct drm_property *modifiers_property;
>
> + /**
> + * @async_modifiers_property: Plane property to list support
> modifier/format
> + * combination for asynchronous flips.
> + */
> + struct drm_property *async_modifiers_property;
> +
> /**
> * @size_hints_property: Plane SIZE_HINTS property.
> */
> diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h index
> dd718c62ac31bf16606f3ee9f025a5b171cd1e67..179da19d602ac94cb6eeea3e
> 6522ae5c7738bb46 100644
> --- a/include/drm/drm_plane.h
> +++ b/include/drm/drm_plane.h
> @@ -549,6 +549,26 @@ struct drm_plane_funcs {
> */
> bool (*format_mod_supported)(struct drm_plane *plane, uint32_t
> format,
> uint64_t modifier);
> + /**
> + * @format_mod_supported_async:
> + *
> + * This optional hook is used for the DRM to determine if for
> + * asynchronous flip the given format/modifier combination is valid
> for
> + * the plane. This allows the DRM to generate the correct format
> + * bitmask (which formats apply to which modifier), and to validate
> + * modifiers at atomic_check time.
> + *
> + * If not present, then any modifier in the plane's modifier
> + * list is allowed with any of the plane's formats.
> + *
This is a bit misleading because userspace still needs to consider IN_FORMATS.
It cannot randomly pair any format with any modifier.
Regards
Chaitanya
> + * Returns:
> + *
> + * True if the given modifier is valid for that format on the plane.
> + * False otherwise.
> + */
> + bool (*format_mod_supported_async)(struct drm_plane *plane,
> + uint32_t format, uint64_t modifier);
> +
> };
>
> /**
>
> --
> 2.25.1
