diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_dp_link_training.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp_link_training.c | 39 |
1 files changed, 28 insertions, 11 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c index 3fcaa98b9055..4da6e33c7fa1 100644 --- a/drivers/gpu/drm/i915/intel_dp_link_training.c +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c @@ -219,32 +219,47 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp) } /* - * Pick training pattern for channel equalization. Training Pattern 3 for HBR2 + * Pick training pattern for channel equalization. Training pattern 4 for HBR3 + * or for 1.4 devices that support it, training Pattern 3 for HBR2 * or 1.2 devices that support it, Training Pattern 2 otherwise. */ static u32 intel_dp_training_pattern(struct intel_dp *intel_dp) { - u32 training_pattern = DP_TRAINING_PATTERN_2; - bool source_tps3, sink_tps3; + bool source_tps3, sink_tps3, source_tps4, sink_tps4; /* + * Intel platforms that support HBR3 also support TPS4. It is mandatory + * for all downstream devices that support HBR3. There are no known eDP + * panels that support TPS4 as of Feb 2018 as per VESA eDP_v1.4b_E1 + * specification. + */ + source_tps4 = intel_dp_source_supports_hbr3(intel_dp); + sink_tps4 = drm_dp_tps4_supported(intel_dp->dpcd); + if (source_tps4 && sink_tps4) { + return DP_TRAINING_PATTERN_4; + } else if (intel_dp->link_rate == 810000) { + if (!source_tps4) + DRM_DEBUG_KMS("8.1 Gbps link rate without source HBR3/TPS4 support\n"); + if (!sink_tps4) + DRM_DEBUG_KMS("8.1 Gbps link rate without sink TPS4 support\n"); + } + /* * Intel platforms that support HBR2 also support TPS3. TPS3 support is * also mandatory for downstream devices that support HBR2. However, not * all sinks follow the spec. */ source_tps3 = intel_dp_source_supports_hbr2(intel_dp); sink_tps3 = drm_dp_tps3_supported(intel_dp->dpcd); - if (source_tps3 && sink_tps3) { - training_pattern = DP_TRAINING_PATTERN_3; - } else if (intel_dp->link_rate == 540000) { + return DP_TRAINING_PATTERN_3; + } else if (intel_dp->link_rate >= 540000) { if (!source_tps3) - DRM_DEBUG_KMS("5.4 Gbps link rate without source HBR2/TPS3 support\n"); + DRM_DEBUG_KMS(">=5.4/6.48 Gbps link rate without source HBR2/TPS3 support\n"); if (!sink_tps3) - DRM_DEBUG_KMS("5.4 Gbps link rate without sink TPS3 support\n"); + DRM_DEBUG_KMS(">=5.4/6.48 Gbps link rate without sink TPS3 support\n"); } - return training_pattern; + return DP_TRAINING_PATTERN_2; } static bool @@ -256,11 +271,13 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) bool channel_eq = false; training_pattern = intel_dp_training_pattern(intel_dp); + /* Scrambling is disabled for TPS2/3 and enabled for TPS4 */ + if (training_pattern != DP_TRAINING_PATTERN_4) + training_pattern |= DP_LINK_SCRAMBLING_DISABLE; /* channel equalization */ if (!intel_dp_set_link_train(intel_dp, - training_pattern | - DP_LINK_SCRAMBLING_DISABLE)) { + training_pattern)) { DRM_ERROR("failed to start channel equalization\n"); return false; } |