drm/i915/dp: add lane_count check in intel_dp_check_link_status

[mirror_ubuntu-bionic-kernel.git] / drivers / gpu / drm / i915 / intel_dp.c

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e03e79f7714a6ddd6e163344b2bdc53aefca5663..f30db8f2425e43e8b23f6b6912de400ce2fd0a6c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4041,6 +4041,11 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
        if (!to_intel_crtc(intel_encoder->base.crtc)->active)
                return;
 
+       /* FIXME: we need to synchronize this sort of stuff with hardware
+        * readout */
+       if (WARN_ON_ONCE(!intel_dp->lane_count))
+               return;
+
        /* if link training is requested we should perform it always */
        if ((intel_dp->compliance_test_type == DP_TEST_LINK_TRAINING) ||
            (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count))) {