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 | 45 |
1 files changed, 32 insertions, 13 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c index 88887938e0bf..0b8eefc2acc5 100644 --- a/drivers/gpu/drm/i915/intel_dp_link_training.c +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c @@ -215,27 +215,46 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp) } } -static void -intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) +/* + * Pick training pattern for channel equalization. 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) { - bool channel_eq = false; - int tries, cr_tries; - uint32_t training_pattern = DP_TRAINING_PATTERN_2; + u32 training_pattern = DP_TRAINING_PATTERN_2; + bool source_tps3, sink_tps3; /* - * Training Pattern 3 for HBR2 or 1.2 devices that support it. - * * Intel platforms that support HBR2 also support TPS3. TPS3 support is - * also mandatory for downstream devices that support HBR2. + * also mandatory for downstream devices that support HBR2. However, not + * all sinks follow the spec. * * Due to WaDisableHBR2 SKL < B0 is the only exception where TPS3 is - * supported but still not enabled. + * supported in source but still not enabled. */ - if (intel_dp_source_supports_hbr2(intel_dp) && - drm_dp_tps3_supported(intel_dp->dpcd)) + 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) - DRM_ERROR("5.4 Gbps link rate without HBR2/TPS3 support\n"); + } else if (intel_dp->link_rate == 540000) { + if (!source_tps3) + DRM_DEBUG_KMS("5.4 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"); + } + + return training_pattern; +} + +static void +intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) +{ + bool channel_eq = false; + int tries, cr_tries; + u32 training_pattern; + + training_pattern = intel_dp_training_pattern(intel_dp); /* channel equalization */ if (!intel_dp_set_link_train(intel_dp, |