The documentation for "drm_plane_funcs.format_mod_supported" reads: This *optional* hook is used for the DRM to determine if 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. However, where the function is not present, an invalid IN_FORMATS blob property with modifiers but no formats is exposed to user-space. This breaks the latest Weston [1]. For testing purposes, I extracted the affected code to a standalone program [2]. Make "create_in_format_blob" behave as documented. [1] https://gitlab.freedesktop.org/wayland/weston/-/blob/9.0/libweston/backend-drm/kms.c#L431 [2] https://github.com/JoseExposito/drm-sandbox/blob/main/in_formats.c Signed-off-by: José Expósito <jose.exposito89@xxxxxxxxx> Reviewed-by: Simon Ser <contact@xxxxxxxxxxx> --- v2: - Remove unused "done:" label to fix compile warning Reported-by: kernel test robot <lkp@xxxxxxxxx> - Add Reviewed-by (thanks to Simon Ser) --- drivers/gpu/drm/drm_plane.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 82afb854141b..deeec60a3315 100644 --- a/drivers/gpu/drm/drm_plane.c +++ b/drivers/gpu/drm/drm_plane.c @@ -202,17 +202,13 @@ static int create_in_format_blob(struct drm_device *dev, struct drm_plane *plane memcpy(formats_ptr(blob_data), plane->format_types, formats_size); - /* If we can't determine support, just bail */ - if (!plane->funcs->format_mod_supported) - goto done; - mod = modifiers_ptr(blob_data); for (i = 0; i < plane->modifier_count; i++) { for (j = 0; j < plane->format_count; j++) { - if (plane->funcs->format_mod_supported(plane, + if (!plane->funcs->format_mod_supported || + plane->funcs->format_mod_supported(plane, plane->format_types[j], plane->modifiers[i])) { - mod->formats |= 1ULL << j; } } @@ -223,7 +219,6 @@ static int create_in_format_blob(struct drm_device *dev, struct drm_plane *plane mod++; } -done: drm_object_attach_property(&plane->base, config->modifiers_property, blob->base.id); -- 2.25.1
