lkml.org 
[lkml]   [2021]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/3] drm/plane: Mention format_mod_supported in IN_FORMATS docs
Date
Adding format modifiers without implementing the function
"drm_plane_funcs.format_mod_supported" exposes an invalid IN_FORMATS
blob with modifiers but no formats to user-space.

This breaks the latest Weston [1]. For testing purposes, I extracted the
affected code to a standalone program [2].

Make clear in the IN_FORMATS documentation that implementing
"format_mod_supported" is mandatory.

[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@gmail.com>
---
drivers/gpu/drm/drm_plane.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 82afb854141b..347571f8909a 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -126,8 +126,11 @@
* IN_FORMATS:
* Blob property which contains the set of buffer format and modifier
* pairs supported by this plane. The blob is a struct
- * drm_format_modifier_blob. Without this property the plane doesn't
- * support buffers with modifiers. Userspace cannot change this property.
+ * drm_format_modifier_blob and the drm_plane_funcs.format_mod_supported
+ * function must be implemented by the driver to determine if the given
+ * format/modifier combination is valid for the plane. Without this property
+ * the plane doesn't support buffers with modifiers. Userspace cannot change
+ * this property.
*
* Note that userspace can check the &DRM_CAP_ADDFB2_MODIFIERS driver
* capability for general modifier support. If this flag is set then every
--
2.25.1
\
 
 \ /
  Last update: 2021-12-21 11:14    [W:0.053 / U:0.724 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site