diff options
| author | Simon Ser <contact@emersion.fr> | 2021-07-21 09:51:30 +0300 |
|---|---|---|
| committer | Simon Ser <contact@emersion.fr> | 2021-07-26 11:08:22 +0300 |
| commit | 3012248fdfeec400accef73bd2957f6d12f87234 (patch) | |
| tree | e3481861ed609db82198a3d4fef1f9c588dbd370 /include/drm/drm_property.h | |
| parent | 03b7c552d081b73ba814eefc257c704b4d096d93 (diff) | |
| download | linux-3012248fdfeec400accef73bd2957f6d12f87234.tar.xz | |
drm: document drm_property_enum.value for bitfields
When a property has the type DRM_MODE_PROP_BITMASK, the value field
stores a bitshift, not a bitmask, which can be surprising.
Signed-off-by: Simon Ser <contact@emersion.fr>
Cc: Leandro Ribeiro <leandro.ribeiro@collabora.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/NUZTPTKKZtAlDhxIXFB1qrUqWBYKapkBxCnb1S1bc3g@cp3-web-033.plabs.ch
Diffstat (limited to 'include/drm/drm_property.h')
| -rw-r--r-- | include/drm/drm_property.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/include/drm/drm_property.h b/include/drm/drm_property.h index bbf5c1fdd7b0..65bc9710a470 100644 --- a/include/drm/drm_property.h +++ b/include/drm/drm_property.h @@ -31,7 +31,6 @@ /** * struct drm_property_enum - symbolic values for enumerations - * @value: numeric property value for this enum entry * @head: list of enum values, linked to &drm_property.enum_list * @name: symbolic name for the enum * @@ -39,6 +38,14 @@ * decoding for each value. This is used for example for the rotation property. */ struct drm_property_enum { + /** + * @value: numeric property value for this enum entry + * + * If the property has the type &DRM_MODE_PROP_BITMASK, @value stores a + * bitshift, not a bitmask. In other words, the enum entry is enabled + * if the bit number @value is set in the property's value. This enum + * entry has the bitmask ``1 << value``. + */ uint64_t value; struct list_head head; char name[DRM_PROP_NAME_LEN]; |