backend-drm: Add GBM_BO_HANDLE as a failure reason

And use it to get a feedback event for when adding scanout tranche.

With this change, I get back a feedback event for dmabuf-feedback
on VC4:

���� tranche: target device /dev/dri/card0, scanout
�   ���� format ABGR2101010, modifier LINEAR (0x0)
�   ���� format XBGR2101010, modifier LINEAR (0x0)
�   ���� format ARGB8888, modifier LINEAR (0x0)
�   ���� format ABGR8888, modifier LINEAR (0x0)
�   ���� format XRGB8888, modifier LINEAR (0x0)
�   ���� format XBGR8888, modifier LINEAR (0x0)
�   ���� format RGB565, modifier LINEAR (0x0)
�   ���� format YUV420, modifier LINEAR (0x0)
�   ���� format YUV422, modifier LINEAR (0x0)
�   ���� format YVU420, modifier LINEAR (0x0)
�   ���� format YVU422, modifier LINEAR (0x0)
�   ���� format NV12, modifier LINEAR (0x0)
�   ���� format NV12, modifier BROADCOM_SAND128 (0x700000000000004)
�   ���� format NV16, modifier LINEAR (0x0)
�   ���� end of tranche

Besides that, it can place a fullscreen state of simple-egl on the
primary plane, which without this change wasn't possible.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>

libweston/backend-drm/drm-internal.h

@@ -246,6 +246,7 @@ enum try_view_on_plane_failure_reasons {
 	FAILURE_REASONS_GLOBAL_ALPHA = 1 << 10,
 	FAILURE_REASONS_NO_GBM = 1 << 11,
 	FAILURE_REASONS_GBM_BO_IMPORT_FAILED = 1 << 12,
+	FAILURE_REASONS_GBM_BO_GET_HANDLE_FAILED = 1 << 13,
 };
 
 /**

libweston/backend-drm/fb.c

@@ -315,8 +315,11 @@ drm_fb_get_from_dmabuf(struct linux_dmabuf_buffer *dmabuf,
 		union gbm_bo_handle handle;
 
 	        handle = gbm_bo_get_handle_for_plane(fb->bo, i);
-		if (handle.s32 == -1)
+		if (handle.s32 == -1) {
+			*try_view_on_plane_failure_reasons |=
+				FAILURE_REASONS_GBM_BO_GET_HANDLE_FAILED;
 			goto err_free;
+		}
 		fb->handles[i] = handle.u32;
 	}
 

libweston/backend-drm/state-propose.c

@@ -341,7 +341,8 @@ dmabuf_feedback_maybe_update(struct drm_backend *b, struct weston_view *ev,
 		(FAILURE_REASONS_ADD_FB_FAILED |
 		 FAILURE_REASONS_FB_FORMAT_INCOMPATIBLE |
 		 FAILURE_REASONS_DMABUF_MODIFIER_INVALID |
-		 FAILURE_REASONS_GBM_BO_IMPORT_FAILED))
+		 FAILURE_REASONS_GBM_BO_IMPORT_FAILED |
+		 FAILURE_REASONS_GBM_BO_GET_HANDLE_FAILED))
 		action_needed |= ACTION_NEEDED_ADD_SCANOUT_TRANCHE;
 
 	assert(action_needed != (ACTION_NEEDED_REMOVE_SCANOUT_TRANCHE |