From 06bfe5b0d892f8120172380694eb66eeb23baf90 Mon Sep 17 00:00:00 2001 From: Rodrigo Vivi Date: Thu, 10 Aug 2017 07:50:43 -0700 Subject: [PATCH] drm/i915: Avoid null dereference if mst_port is unset. I'm not sure if this is really the case and I don't believe this is the real fix for the bug mentioned here, but since I don't see a reliable path when mst_port is set and when mode_valid is requested I believe it is worth to have this protection here. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102022 Cc: Elizabeth Cc: Stefan Assmann Cc: Dhinakaran Pandiyan Signed-off-by: Rodrigo Vivi Reviewed-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20170810145043.24047-1-rodrigo.vivi@intel.com --- drivers/gpu/drm/i915/intel_dp_mst.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index 58568559711a..93fc8ab9bb31 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -370,6 +370,9 @@ intel_dp_mst_mode_valid(struct drm_connector *connector, int bpp = 24; /* MST uses fixed bpp */ int max_rate, mode_rate, max_lanes, max_link_clock; + if (!intel_dp) + return MODE_ERROR; + max_link_clock = intel_dp_max_link_rate(intel_dp); max_lanes = intel_dp_max_lane_count(intel_dp); -- 2.30.2