[PATCH 2/5] drm/uapi: Introduce the DRM_MODE_DUMB_CURSOR flag

[Ville Syrjala <ville.syrjala@linux.intel.com>]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

On certain hardware (eg. all Intel GPUs) normal planes vs. cursor
planes have wildly different hardware capabilities. Currently
DRM_IOCTL_MODE_CREATE_DUMB is only really suitable for allocating
buffers for normal planes.

Introduce a new DRM_MODE_DUMB_CURSOR flag for DRM_IOCTL_MODE_CREATE_DUMB
so that the driver can attempt to make sure the dumb buffer will
be actually suitable for cursor planes.

Cc: Daniel Stone <daniels@collabora.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/drm_dumb_buffers.c | 2 +-
 include/uapi/drm/drm_mode.h        | 4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_dumb_buffers.c b/drivers/gpu/drm/drm_dumb_buffers.c
index fdc249198022..e4a9692c099d 100644
--- a/drivers/gpu/drm/drm_dumb_buffers.c
+++ b/drivers/gpu/drm/drm_dumb_buffers.c
@@ -197,7 +197,7 @@ int drm_mode_create_dumb(struct drm_device *dev,
 		return -ENOSYS;
 	if (!args->width || !args->height || !args->bpp)
 		return -EINVAL;
-	if (args->flags)
+	if (args->flags & ~DRM_MODE_DUMB_CURSOR)
 		return -EINVAL;
 
 	/* overflow checks for 32bit size calculations */
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 1e0e02a79b5c..3b7e13a29244 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -1062,12 +1062,14 @@ struct drm_mode_crtc_page_flip_target {
 	__u64 user_data;
 };
 
+#define DRM_MODE_DUMB_CURSOR	(1<<0) /* dumb buffer is intended for a cursor */
+
 /**
  * struct drm_mode_create_dumb - Create a KMS dumb buffer for scanout.
  * @height: buffer height in pixels
  * @width: buffer width in pixels
  * @bpp: color mode
- * @flags: must be zero
+ * @flags: bitmask of flags, see DRM_MODE_DUMB_* defines
  * @handle: buffer object handle
  * @pitch: number of bytes between two consecutive lines
  * @size: size of the whole buffer in bytes
-- 
2.49.1