From 081dc436010856022aaa6890c97c66c308b13580 Mon Sep 17 00:00:00 2001 From: Gary Wang Date: Fri, 23 Oct 2015 16:01:24 +0800 Subject: [PATCH] drm/i915: not enter MST mode during DP probing for DisplayPort MST-enabled Hub It found some DP MST-enabled hub causing problem of DP link computation, and need to disable its MST support. This is a workaround, and need to be fixed further. References: https://bugs.freedesktop.org/show_bug.cgi?id=91791 Signed-off-by: Gary Wang --- drivers/gpu/drm/i915/intel_dp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) mode change 100644 => 100755 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 old mode 100644 new mode 100755 index 8287df4..4dd74b1 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -4086,7 +4086,10 @@ intel_dp_probe_mst(struct intel_dp *intel_dp) if (!intel_dp->can_mst) return false; - if (intel_dp->dpcd[DP_DPCD_REV] < 0x12) + //TO-DO, this is workaround for test purpose only on disabling DP 1.2 MST + //SKL-U suffers error from DP data link computation with DP MST enabled. + //fix-BUG https://bugs.freedesktop.org/show_bug.cgi?id=91791 + if (intel_dp->dpcd[DP_DPCD_REV] <= 0x12) return false; if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_MSTM_CAP, buf, 1)) { -- 1.9.1