[0452/1094] drm: Specify a bit more the DRM_CAP_CURSOR_{WIDTH, HEIGHT} caps

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 10:50 a.m. UTC

From: "Lespiau, Damien" <[e-mail]>

Earlier this week, there was a bit of confusion about those new
capabilities, to the point I think it's better to document the intention
and API contract.

The comment documents the current situation:
 - the radeon driver returns the only valid size for the hw
 - i915 returns the maximun cursor size
 - other drivers fall back to returning 64x64

The common contract is to return a valid cursor size.

Cc: Sagar Kamble <[e-mail]>
Cc: Chris Wilson <[e-mail]>
Cc: Alex Deucher <[e-mail]>
Cc: Imre Deak <[e-mail]>
Signed-off-by: Damien Lespiau <[e-mail]>
Reviewed-by: Chris Wilson <[e-mail]>
Reviewed-by: Alex Deucher <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>
(cherry picked from commit bfe8b5738a5d99156d83dc298729552ce82309d5)

Signed-off-by: Dheeraj Jamwal <[e-mail]>
---
 include/uapi/drm/drm.h |    9 +++++++++
 1 file changed, 9 insertions(+)

Patch

diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 6e4952b..9abbeb9 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -619,6 +619,15 @@  struct drm_gem_open {
 #define  DRM_PRIME_CAP_EXPORT		0x2
 #define DRM_CAP_TIMESTAMP_MONOTONIC	0x6
 #define DRM_CAP_ASYNC_PAGE_FLIP		0x7
+/*
+ * The CURSOR_WIDTH and CURSOR_HEIGHT capabilities return a valid widthxheight
+ * combination for the hardware cursor. The intention is that a hardware
+ * agnostic userspace can query a cursor plane size to use.
+ *
+ * Note that the cross-driver contract is to merely return a valid size;
+ * drivers are free to attach another meaning on top, eg. i915 returns the
+ * maximum plane size.
+ */
 #define DRM_CAP_CURSOR_WIDTH		0x8
 #define DRM_CAP_CURSOR_HEIGHT		0x9