[PATCH xf86-video-amdgpu] Bail from drmmode_cm_init if there's no CRTC

[michel@xxxxxxxxxxx (Michel Dänzer)]

From: Michel Dänzer <michel.daenzer@xxxxxxx>

We would crash due to dereferencing the NULL mode_res->crtc pointer.

Bugzilla: https://bugs.freedesktop.org/107913
Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 src/drmmode_display.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/drmmode_display.c b/src/drmmode_display.c
index 6ef6a98e2..cbda8ad35 100644
--- a/src/drmmode_display.c
+++ b/src/drmmode_display.c
@@ -3198,6 +3198,9 @@ static void drmmode_cm_init(int drm_fd, drmmode_ptr drmmode,
 	memset(drmmode->cm_prop_ids, 0, sizeof(drmmode->cm_prop_ids));
 	drmmode->gamma_lut_size = drmmode->degamma_lut_size = 0;
 
+	if (!mode_res->crtcs)
+		return;
+
 	/* AMD hardware has color management support on all pipes. It is
 	 * therefore sufficient to only check the first CRTC.
 	 */
-- 
2.19.0.rc2