[PATCH i-g-t v15 1/5] lib/igt_kms: Add support to retrieve async modifiers and formats

[Karthik B S]

On 6/23/2025 4:39 PM, Santhosh Reddy Guddati wrote:
> Parse "IN_FORMATS_ASYNC" plane property to identify supported
> format modifier pairs for async flips
>
> V2: Add new fields async_formats and reset idx.
>
> V3: Improve commit message , remove unused declaration (Chaitanya)
>      Introduce structure to hold a format modifier and its
>      associated format list.
>
> V4: Implement format+modifier tuples for async similar to IN_FORMATS
>      (Chaitanya).
>
> V5: Re use local variables for async formats and free blob after
>      usage(Chaitanya)
>
> V6: Initialize async_modifiers and async_formats to NULL. (Chaitanya)
>
> V7: Fix async format count to return 0 on failures (Chaitanya)
>
> V8: Refactor parsing blob to a common function. (Ville)
>
> Signed-off-by: Santhosh Reddy Guddati <santhosh.reddy.guddati at intel.com>
> Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
Reviewed-by: Karthik B S <karthik.b.s at intel.com>
> ---
>   lib/igt_kms.c | 73 +++++++++++++++++++++++++++++++--------------------
>   lib/igt_kms.h |  7 ++++-
>   2 files changed, 50 insertions(+), 30 deletions(-)
>
> diff --git a/lib/igt_kms.c b/lib/igt_kms.c
> index 9ee03e870..599901ee8 100644
> --- a/lib/igt_kms.c
> +++ b/lib/igt_kms.c
> @@ -701,6 +701,7 @@ const char * const igt_plane_prop_names[IGT_NUM_PLANE_PROPS] = {
>   	[IGT_PLANE_FB_DAMAGE_CLIPS] = "FB_DAMAGE_CLIPS",
>   	[IGT_PLANE_SCALING_FILTER] = "SCALING_FILTER",
>   	[IGT_PLANE_SIZE_HINTS] = "SIZE_HINTS",
> +	[IGT_PLANE_IN_FORMATS_ASYNC] = "IN_FORMATS_ASYNC",
>   };
>   
>   const char * const igt_crtc_prop_names[IGT_NUM_CRTC_PROPS] = {
> @@ -5786,13 +5787,43 @@ static int igt_count_plane_format_mod(const struct drm_format_modifier_blob *blo
>   	return count;
>   }
>   
> +static void igt_parse_format_mod_blob(const struct drm_format_modifier_blob *blob_data,
> +				      uint32_t **formats, uint64_t **modifiers, int *count)
> +{
> +	const struct drm_format_modifier *m = modifiers_ptr(blob_data);
> +	const uint32_t *f = formats_ptr(blob_data);
> +	int idx = 0;
> +
> +	*count = igt_count_plane_format_mod(blob_data);
> +	if (*count == 0)
> +		return;
> +
> +	*formats = calloc(*count, sizeof((*formats)[0]));
> +	igt_assert(*formats);
> +	*modifiers = calloc(*count, sizeof((*modifiers)[0]));
> +	igt_assert(*modifiers);
> +
> +	for (int i = 0; i < blob_data->count_modifiers; i++) {
> +		for (int j = 0; j < 64; j++) {
> +			if (!(m[i].formats & (1ULL << j)))
> +				continue;
> +
> +			(*formats)[idx] = f[m[i].offset + j];
> +			(*modifiers)[idx] = m[i].modifier;
> +			idx++;
> +			igt_assert_lte(idx, *count);
> +		}
> +	}
> +
> +	igt_assert_eq(idx, *count);
> +}
> +
>   static void igt_fill_plane_format_mod(igt_display_t *display, igt_plane_t *plane)
>   {
>   	const struct drm_format_modifier_blob *blob_data;
>   	drmModePropertyBlobPtr blob;
>   	uint64_t blob_id;
> -	int idx = 0;
> -	int count;
> +	int count = 0;
>   
>   	if (!igt_plane_has_prop(plane, IGT_PLANE_IN_FORMATS)) {
>   		drmModePlanePtr p = plane->drm_plane;
> @@ -5818,40 +5849,24 @@ static void igt_fill_plane_format_mod(igt_display_t *display, igt_plane_t *plane
>   	}
>   
>   	blob_id = igt_plane_get_prop(plane, IGT_PLANE_IN_FORMATS);
> -
>   	blob = drmModeGetPropertyBlob(display->drm_fd, blob_id);
>   	if (!blob)
>   		return;
>   
> -	blob_data = (const struct drm_format_modifier_blob *) blob->data;
> -
> -	count = igt_count_plane_format_mod(blob_data);
> -	if (!count)
> -		return;
> -
> -	plane->format_mod_count = count;
> -	plane->formats = calloc(count, sizeof(plane->formats[0]));
> -	igt_assert(plane->formats);
> -	plane->modifiers = calloc(count, sizeof(plane->modifiers[0]));
> -	igt_assert(plane->modifiers);
> +	blob_data = (const struct drm_format_modifier_blob *)blob->data;
> +	igt_parse_format_mod_blob(blob_data, &plane->formats, &plane->modifiers, &plane->format_mod_count);
> +	drmModeFreePropertyBlob(blob);
>   
> -	for (int i = 0; i < blob_data->count_modifiers; i++) {
> -		for (int j = 0; j < 64; j++) {
> -			const struct drm_format_modifier *modifiers =
> -				modifiers_ptr(blob_data);
> -			const uint32_t *formats = formats_ptr(blob_data);
> -
> -			if (!(modifiers[i].formats & (1ULL << j)))
> -				continue;
> +	if (igt_plane_has_prop(plane, IGT_PLANE_IN_FORMATS_ASYNC)) {
> +		blob_id = igt_plane_get_prop(plane, IGT_PLANE_IN_FORMATS_ASYNC);
> +		blob = drmModeGetPropertyBlob(display->drm_fd, blob_id);
> +		if (!blob)
> +			return;
>   
> -			plane->formats[idx] = formats[modifiers[i].offset + j];
> -			plane->modifiers[idx] = modifiers[i].modifier;
> -			idx++;
> -			igt_assert_lte(idx, plane->format_mod_count);
> -		}
> +		blob_data = (const struct drm_format_modifier_blob *)blob->data;
> +		igt_parse_format_mod_blob(blob_data, &plane->async_formats, &plane->async_modifiers, &plane->async_format_mod_count);
> +		drmModeFreePropertyBlob(blob);
>   	}
> -
> -	igt_assert_eq(idx, plane->format_mod_count);
>   }
>   
>   /**
> diff --git a/lib/igt_kms.h b/lib/igt_kms.h
> index a85fee515..7bc1a6886 100644
> --- a/lib/igt_kms.h
> +++ b/lib/igt_kms.h
> @@ -365,7 +365,8 @@ enum igt_atomic_plane_properties {
>          IGT_PLANE_HOTSPOT_X,
>          IGT_PLANE_HOTSPOT_Y,
>          IGT_PLANE_SIZE_HINTS,
> -       IGT_NUM_PLANE_PROPS
> +       IGT_PLANE_IN_FORMATS_ASYNC,
> +       IGT_NUM_PLANE_PROPS,
>   };
>   
>   /**
> @@ -438,6 +439,10 @@ typedef struct igt_plane {
>   	uint64_t *modifiers;
>   	uint32_t *formats;
>   	int format_mod_count;
> +
> +	uint64_t *async_modifiers;
> +	uint32_t *async_formats;
> +	int async_format_mod_count;
>   } igt_plane_t;
>   
>   /*