From b0f7095f8bd503eddf9a91a258e796da0058f182 Mon Sep 17 00:00:00 2001 From: Mika Kahola Date: Mon, 20 Jun 2016 11:10:26 +0300 Subject: drm/i915: Revert DisplayPort fast link training feature commit 34511dce4b35685d3988d5c8b100d11a068db5bd upstream. It has been found out that in some HW combination the DisplayPort fast link training feature caused screen flickering. Let's revert this feature for now until we can ensure that the feature works for all platforms. This is a manual revert of commits 5fa836a9d859 ("drm/i915: DP link training optimization") and 4e96c97742f4 ("drm/i915: eDP link training optimization"). Fixes: 5fa836a9d859 ("drm/i915: DP link training optimization") Fixes: 4e96c97742f4 ("drm/i915: eDP link training optimization") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91393 Reviewed-by: Jani Nikula Signed-off-by: Mika Kahola Signed-off-by: Jani Nikula Link: http://patchwork.freedesktop.org/patch/msgid/1466410226-19543-1-git-send-email-mika.kahola@intel.com (cherry picked from commit 91df09d92ad82c8778ca218097bf827f154292ca) Signed-off-by: Joakim Tjernlund Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/intel_dp.c | 3 --- drivers/gpu/drm/i915/intel_dp_link_training.c | 25 ++----------------------- drivers/gpu/drm/i915/intel_drv.h | 2 -- 3 files changed, 2 insertions(+), 28 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index dee76b9657f8..69054ef978fa 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -5022,9 +5022,6 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd) intel_display_power_get(dev_priv, power_domain); if (long_hpd) { - /* indicate that we need to restart link training */ - intel_dp->train_set_valid = false; - if (!intel_digital_port_connected(dev_priv, intel_dig_port)) goto mst_fail; diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c index 0b8eefc2acc5..926a1e6ea2f6 100644 --- a/drivers/gpu/drm/i915/intel_dp_link_training.c +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c @@ -85,8 +85,7 @@ static bool intel_dp_reset_link_train(struct intel_dp *intel_dp, uint8_t dp_train_pat) { - if (!intel_dp->train_set_valid) - memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set)); + memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set)); intel_dp_set_signal_levels(intel_dp); return intel_dp_set_link_train(intel_dp, dp_train_pat); } @@ -161,22 +160,6 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp) break; } - /* - * if we used previously trained voltage and pre-emphasis values - * and we don't get clock recovery, reset link training values - */ - if (intel_dp->train_set_valid) { - DRM_DEBUG_KMS("clock recovery not ok, reset"); - /* clear the flag as we are not reusing train set */ - intel_dp->train_set_valid = false; - if (!intel_dp_reset_link_train(intel_dp, - DP_TRAINING_PATTERN_1 | - DP_LINK_SCRAMBLING_DISABLE)) { - DRM_ERROR("failed to enable link training\n"); - return; - } - continue; - } /* Check to see if we've tried the max voltage */ for (i = 0; i < intel_dp->lane_count; i++) @@ -284,7 +267,6 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) /* Make sure clock is still ok */ if (!drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) { - intel_dp->train_set_valid = false; intel_dp_link_training_clock_recovery(intel_dp); intel_dp_set_link_train(intel_dp, training_pattern | @@ -301,7 +283,6 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) /* Try 5 times, then try clock recovery if that fails */ if (tries > 5) { - intel_dp->train_set_valid = false; intel_dp_link_training_clock_recovery(intel_dp); intel_dp_set_link_train(intel_dp, training_pattern | @@ -322,10 +303,8 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) intel_dp_set_idle_link_train(intel_dp); - if (channel_eq) { - intel_dp->train_set_valid = true; + if (channel_eq) DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n"); - } } void intel_dp_stop_link_train(struct intel_dp *intel_dp) diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 3a30b37d6885..8dd2cc56451f 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -811,8 +811,6 @@ struct intel_dp { /* This is called before a link training is starterd */ void (*prepare_link_retrain)(struct intel_dp *intel_dp); - bool train_set_valid; - /* Displayport compliance testing */ unsigned long compliance_test_type; unsigned long compliance_test_data; -- cgit v1.2.3