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-d... [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 | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 82afb854141b..c1186b7215ee 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; } }

Fix minor typo: "valdiate" -> "validate".

Signed-off-by: José Expósito jose.exposito89@gmail.com --- include/drm/drm_plane.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h index 0c1102dc4d88..06759badf99f 100644 --- a/include/drm/drm_plane.h +++ b/include/drm/drm_plane.h @@ -516,7 +516,7 @@ struct drm_plane_funcs { * 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 valdiate modifiers at atomic_check time. + * 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.

The "drm_plane_funcs.format_mod_supported" can be removed in favor of the default implementation.

Signed-off-by: José Expósito jose.exposito89@gmail.com --- drivers/gpu/drm/drm_simple_kms_helper.c | 8 -------- 1 file changed, 8 deletions(-)

diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c index 72989ed1baba..2c6aa67c6956 100644 --- a/drivers/gpu/drm/drm_simple_kms_helper.c +++ b/drivers/gpu/drm/drm_simple_kms_helper.c @@ -284,13 +284,6 @@ static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane, pipe->funcs->cleanup_fb(pipe, state); }

-static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane, - uint32_t format, - uint64_t modifier) -{ - return modifier == DRM_FORMAT_MOD_LINEAR; -} - static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = { .prepare_fb = drm_simple_kms_plane_prepare_fb, .cleanup_fb = drm_simple_kms_plane_cleanup_fb, @@ -339,7 +332,6 @@ static const struct drm_plane_funcs drm_simple_kms_plane_funcs = { .reset = drm_simple_kms_plane_reset, .atomic_duplicate_state = drm_simple_kms_plane_duplicate_state, .atomic_destroy_state = drm_simple_kms_plane_destroy_state, - .format_mod_supported = drm_simple_kms_format_mod_supported, };

/**

The "drm_plane_funcs.format_mod_supported" can be removed in favor of the default implementation.

Signed-off-by: José Expósito jose.exposito89@gmail.com --- drivers/gpu/drm/mxsfb/mxsfb_kms.c | 8 -------- 1 file changed, 8 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index 0655582ae8ed..df32e1c3cc5d 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c @@ -554,13 +554,6 @@ static void mxsfb_plane_overlay_atomic_update(struct drm_plane *plane, writel(ctrl, mxsfb->base + LCDC_AS_CTRL); }

-static bool mxsfb_format_mod_supported(struct drm_plane *plane, - uint32_t format, - uint64_t modifier) -{ - return modifier == DRM_FORMAT_MOD_LINEAR; -} - static const struct drm_plane_helper_funcs mxsfb_plane_primary_helper_funcs = { .atomic_check = mxsfb_plane_atomic_check, .atomic_update = mxsfb_plane_primary_atomic_update, @@ -572,7 +565,6 @@ static const struct drm_plane_helper_funcs mxsfb_plane_overlay_helper_funcs = { };

static const struct drm_plane_funcs mxsfb_plane_funcs = { - .format_mod_supported = mxsfb_format_mod_supported, .update_plane = drm_atomic_helper_update_plane, .disable_plane = drm_atomic_helper_disable_plane, .destroy = drm_plane_cleanup,