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 <cont...@emersion.fr>
Cc: Pekka Paalanen <pekka.paala...@collabora.com>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Cc: Leandro Ribeiro <leandro.ribe...@collabora.com>
---
include/drm/drm_property.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/drm/drm_property.h b/include/drm/drm_property.h
index bbf5c1fdd7b0..f3ea7f97f372 100644
--- a/include/drm/drm_property.h
+++ b/include/drm/drm_property.h
@@ -37,6 +37,11 @@
*
* For enumeration and bitmask properties this structure stores the symbolic
* decoding for each value. This is used for example for the rotation property.
+ *
+ * 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``.
*/
struct drm_property_enum {
uint64_t value;
--
2.32.0
