From 710a97d847ff6463c3671328d3f5853f5b33fe8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= <jose.exposito89@gmail.com>
Date: Sun, 26 Dec 2021 12:24:58 +0100
Subject: drm/plane: Make format_mod_supported truly optional
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Git-commit: d14f0c205302648df29c494a1a81ec3d897a2552
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
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@gmail.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patchwork.freedesktop.org/patch/msgid/20211226112503.31771-2-jose.exposito89@gmail.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
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);
--
2.38.1