[RFC PATCH] drm: Add new fb flags to pass interlaced alternate field information

[Satish Kumar Nagireddy]

This patch adds two new framebuffer flags, so that application can
communicate alternate interlaced field information to DRM.

This patch also modifies the validation of framebuffer flags in DRM
core framework. This is to ensure that application is setting the
right framebuffer flags.

Signed-off-by: Satish Kumar Nagireddy <satish.nagireddy.nagireddy at xilinx.com>
---
 drivers/gpu/drm/drm_framebuffer.c | 3 ++-
 include/uapi/drm/drm_mode.h       | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index 28a0108..d330256 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -241,7 +241,8 @@ drm_internal_framebuffer_create(struct drm_device *dev,
 	struct drm_framebuffer *fb;
 	int ret;
 
-	if (r->flags & ~(DRM_MODE_FB_INTERLACED | DRM_MODE_FB_MODIFIERS)) {
+	if (r->flags & ~(DRM_MODE_FB_INTERLACED | DRM_MODE_FB_MODIFIERS |
+		DRM_MODE_FB_ALTERNATE_TOP | DRM_MODE_FB_ALTERNATE_BOTTOM)) {
 		DRM_DEBUG_KMS("bad framebuffer flags 0x%08x\n", r->flags);
 		return ERR_PTR(-EINVAL);
 	}
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index ce7efe2..b857ed4 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -388,6 +388,8 @@ struct drm_mode_fb_cmd {
 
 #define DRM_MODE_FB_INTERLACED	(1<<0) /* for interlaced framebuffers */
 #define DRM_MODE_FB_MODIFIERS	(1<<1) /* enables ->modifer[] */
+#define DRM_MODE_FB_ALTERNATE_TOP	(1<<2) /* for alternate top field */
+#define DRM_MODE_FB_ALTERNATE_BOTTOM	(1<<3) /* for alternate bottom field */
 
 struct drm_mode_fb_cmd2 {
 	__u32 fb_id;
-- 
2.7.4