gbm: Add a gbm_device_get_format_modifier_plane_count function

This allows the user to query the number of planes required by a given
format+modifier combination without having to create a bo or surface.

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_dri.c
index 46285245658..0a4853bf63d 100644
--- a/src/gbm/backends/dri/gbm_dri.c
+++ b/src/gbm/backends/dri/gbm_dri.c
@@ -640,6 +640,30 @@ gbm_dri_is_format_supported(struct gbm_device *gbm,
 }
 
 static int
+gbm_dri_get_format_modifier_plane_count(struct gbm_device *gbm,
+                                        uint32_t format,
+                                        uint64_t modifier)
+{
+   struct gbm_dri_device *dri = gbm_dri_device(gbm);
+   uint64_t plane_count;
+
+   if (dri->image->base.version < 16 ||
+       !dri->image->queryDmaBufFormatModifierAttribs)
+      return -1;
+
+   format = gbm_format_canonicalize(format);
+   if (gbm_format_to_dri_format(format) == 0)
+      return -1;
+
+   if (!dri->image->queryDmaBufFormatModifierAttribs(
+         dri->screen, format, modifier,
+         __DRI_IMAGE_FORMAT_MODIFIER_ATTRIB_PLANE_COUNT, &plane_count))
+      return -1;
+
+   return plane_count;
+}
+
+static int
 gbm_dri_bo_write(struct gbm_bo *_bo, const void *buf, size_t count)
 {
    struct gbm_dri_bo *bo = gbm_dri_bo(_bo);
@@ -1350,6 +1374,8 @@ dri_device_create(int fd)
    dri->base.bo_map = gbm_dri_bo_map;
    dri->base.bo_unmap = gbm_dri_bo_unmap;
    dri->base.is_format_supported = gbm_dri_is_format_supported;
+   dri->base.get_format_modifier_plane_count =
+      gbm_dri_get_format_modifier_plane_count;
    dri->base.bo_write = gbm_dri_bo_write;
    dri->base.bo_get_fd = gbm_dri_bo_get_fd;
    dri->base.bo_get_planes = gbm_dri_bo_get_planes;