[PATCH] drm: don't override possible_crtcs for primary/cursor planes

[Rob Clark]

It is kind of a pointless restriction.  If userspace does silly things
like using crtcA's cursor plane on crtcB, and then setcursor on crtcA,
it will end up with the overlay disabled on crtcB.  But userspace is
allowed to shoot itself like this.

v2: don't WARN_ON() if caller did not set ->possible_crtcs.  This keeps
    the existing behavior by default, if caller does not set the
    ->possible_crtcs.

Signed-off-by: Rob Clark <robdclark at gmail.com>
---
 drivers/gpu/drm/drm_crtc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 13441e2..ce274ed 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -229,9 +229,9 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 
 	crtc->primary = primary;
 	crtc->cursor = cursor;
-	if (primary)
+	if (primary && !primary->possible_crtcs)
 		primary->possible_crtcs = 1 << drm_crtc_index(crtc);
-	if (cursor)
+	if (cursor && !cursor->possible_crtcs)
 		cursor->possible_crtcs = 1 << drm_crtc_index(crtc);
 
 	ret = drm_crtc_crc_init(crtc);
-- 
2.7.4