diff mbox series

[1/3] drm: drm_blend.c: Add precision in drm_rotation_simplify kernel doc

Message ID 20240409-google-drm-doc-v1-1-033d55cc8250@bootlin.com (mailing list archive)
State New, archived
Headers show
Series drm: Multiple documentation update | expand

Commit Message

Louis Chauvet April 9, 2024, 10:04 a.m. UTC
As the function uses non-trivial bit operations, add a little paragraph
to describe what is the expected behavior.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/drm_blend.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Bagas Sanjaya April 15, 2024, 2:30 p.m. UTC | #1
On Tue, Apr 09, 2024 at 12:04:05PM +0200, Louis Chauvet wrote:
> diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> index 6e74de833466..8d4b317eb9d7 100644
> --- a/drivers/gpu/drm/drm_blend.c
> +++ b/drivers/gpu/drm/drm_blend.c
> @@ -321,6 +321,11 @@ EXPORT_SYMBOL(drm_plane_create_rotation_property);
>   * transforms the hardware supports, this function may not
>   * be able to produce a supported transform, so the caller should
>   * check the result afterwards.
> + *
> + * If the rotation is not fully supported, this function will add a rotation of 180
> + * (ROTATE_90 would become ROTATE_270) and add a reflection on X and Y.
> + * The resulting transformation is the same (REFLECT_X | REFLECT_Y | ROTATE_180
> + * is a no-op), but some unsupported flags are removed.
>   */
>  unsigned int drm_rotation_simplify(unsigned int rotation,
>  				   unsigned int supported_rotations)
> 

The wording LGTM, thanks!

Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index 6e74de833466..8d4b317eb9d7 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -321,6 +321,11 @@  EXPORT_SYMBOL(drm_plane_create_rotation_property);
  * transforms the hardware supports, this function may not
  * be able to produce a supported transform, so the caller should
  * check the result afterwards.
+ *
+ * If the rotation is not fully supported, this function will add a rotation of 180
+ * (ROTATE_90 would become ROTATE_270) and add a reflection on X and Y.
+ * The resulting transformation is the same (REFLECT_X | REFLECT_Y | ROTATE_180
+ * is a no-op), but some unsupported flags are removed.
  */
 unsigned int drm_rotation_simplify(unsigned int rotation,
 				   unsigned int supported_rotations)