From: Ville Syrjälä Date: Tue, 12 May 2020 17:41:44 +0000 (+0300) Subject: drm/i915: Fix DP_TRAIN_MAX_{PRE_EMPHASIS,SWING}_REACHED handling X-Git-Tag: v5.9-rc1~134^2~18^2~27 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3625a1f5bf6ba47fbd903be1d63dade9a48e8e72;p=thirdparty%2Fkernel%2Flinux.git drm/i915: Fix DP_TRAIN_MAX_{PRE_EMPHASIS,SWING}_REACHED handling The DP spec says: "The transmitter shall support at least three levels of voltage swing (Levels 0, 1, and 2). If only three levels of voltage swing are supported (VOLTAGE SWING SET field (bits 1:0) are programmed to 10 (Level 2)), this bit shall be set to 1, and cleared in all other cases. If all four levels of voltage swing are supported (VOLTAGE SWING SET field (bits 1:0) are programmed to 11 (Level 3)), this bit shall be set to 1,and cleared in all other cases." Let's follow that exactly instead of the current apporach where we can set those also for vswing/preemph levels 0 or 1 (or 2 when the platform max is 3). Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20200512174145.3186-7-ville.syrjala@linux.intel.com Reviewed-by: Imre Deak --- diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c index b9e4ee2dbddc9..2493142a70e97 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c @@ -67,8 +67,9 @@ void intel_dp_get_adjust_train(struct intel_dp *intel_dp, if (p >= preemph_max) p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED; - voltage_max = min(intel_dp->voltage_max(intel_dp), - dp_voltage_max(p)); + v = min(v, dp_voltage_max(p)); + + voltage_max = intel_dp->voltage_max(intel_dp); if (v >= voltage_max) v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;