drm: introduce fb_modifiers_not_supported flag in mode_config

If only linear modifier is advertised, since there are many drivers that
only linear supported, the DRM core should handle this rather than
open-coding in every driver. However, there are legacy drivers such as
radeon that do not support modifiers but infer the actual layout of the
underlying buffer. Therefore, a new flag fb_modifiers_not_supported is
introduced for these legacy drivers, and allow_fb_modifiers is replaced
with this new flag.

v3:
 - change the order as follows:
   1. add fb_modifiers_not_supported flag
   2. add default modifiers
   3. remove allow_fb_modifiers flag
 - add a conditional disable in amdgpu_dm_plane_init()

v4:
 - modify kernel docs

v5:
 - modify kernel docs

Signed-off-by: Tomohito Esaki <[email protected]>
Acked-by: Harry Wentland <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 39812daeb7c5..e8a994559b65 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7828,6 +7828,9 @@ static int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
 	if (res)
 		return res;
 
+	if (modifiers == NULL)
+		adev_to_drm(dm->adev)->mode_config.fb_modifiers_not_supported = true;
+
 	res = drm_universal_plane_init(adev_to_drm(dm->adev), plane, possible_crtcs,
 				       &dm_plane_funcs, formats, num_formats,
 				       modifiers, plane->type, NULL);