[PATCH] drm: Don't create the IN_FORMATS blob when the driver does not provide .format_mod_supported()

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

The code responsible for creating the IN_FORMATS
blob is broken when the driver doesn't provide a
.format_mod_supported() hook. It just copies in
the format list, but leaves all the modifier information
zeroed. That would indicate (in a very silly way) that
there are in fact no supported format+modifier combinations.
That is utter nonsense.

Let's just not create the blob at all in that case. The
alternative would be to assume all format+mod combos will
work and populate it accordingly. But I'm not convinced we
can make that promise to userspace for all the drivers.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/drm_plane.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index e6231947f987..202a2b680947 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -124,10 +124,6 @@ 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++) {
@@ -145,7 +141,6 @@ 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);
 
@@ -281,7 +276,7 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,
 		drm_object_attach_property(&plane->base, config->prop_src_h, 0);
 	}
 
-	if (config->allow_fb_modifiers)
+	if (config->allow_fb_modifiers && funcs->format_mod_supported)
 		create_in_format_blob(dev, plane);
 
 	return 0;
-- 
2.26.2