diff options
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dp_link_training.c | 36 |
1 files changed, 15 insertions, 21 deletions
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 d5ec8f35e708..892d7db7d94f 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c @@ -34,18 +34,6 @@ intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE]) link_status[3], link_status[4], link_status[5]); } -static int intel_dp_lttpr_count(struct intel_dp *intel_dp) -{ - int count = drm_dp_lttpr_count(intel_dp->lttpr_common_caps); - - /* - * Pretend no LTTPRs in case of LTTPR detection error, or - * if too many (>8) LTTPRs are detected. This translates to link - * training in transparent mode. - */ - return count <= 0 ? 0 : count; -} - static void intel_dp_reset_lttpr_count(struct intel_dp *intel_dp) { intel_dp->lttpr_common_caps[DP_PHY_REPEATER_CNT - @@ -142,6 +130,17 @@ int intel_dp_lttpr_init(struct intel_dp *intel_dp) return 0; ret = intel_dp_read_lttpr_common_caps(intel_dp); + if (!ret) + return 0; + + lttpr_count = drm_dp_lttpr_count(intel_dp->lttpr_common_caps); + /* + * Prevent setting LTTPR transparent mode explicitly if no LTTPRs are + * detected as this breaks link training at least on the Dell WD19TB + * dock. + */ + if (lttpr_count == 0) + return 0; /* * See DP Standard v2.0 3.6.6.1. about the explicit disabling of @@ -150,17 +149,12 @@ int intel_dp_lttpr_init(struct intel_dp *intel_dp) */ intel_dp_set_lttpr_transparent_mode(intel_dp, true); - if (!ret) - return 0; - - lttpr_count = intel_dp_lttpr_count(intel_dp); - /* * In case of unsupported number of LTTPRs or failing to switch to * non-transparent mode fall-back to transparent link training mode, * still taking into account any LTTPR common lane- rate/count limits. */ - if (lttpr_count == 0) + if (lttpr_count < 0) return 0; if (!intel_dp_set_lttpr_transparent_mode(intel_dp, false)) { @@ -222,11 +216,11 @@ intel_dp_phy_is_downstream_of_source(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy) { struct drm_i915_private *i915 = dp_to_i915(intel_dp); - int lttpr_count = intel_dp_lttpr_count(intel_dp); + int lttpr_count = drm_dp_lttpr_count(intel_dp->lttpr_common_caps); - drm_WARN_ON_ONCE(&i915->drm, lttpr_count == 0 && dp_phy != DP_PHY_DPRX); + drm_WARN_ON_ONCE(&i915->drm, lttpr_count <= 0 && dp_phy != DP_PHY_DPRX); - return lttpr_count == 0 || dp_phy == DP_PHY_LTTPR(lttpr_count - 1); + return lttpr_count <= 0 || dp_phy == DP_PHY_LTTPR(lttpr_count - 1); } static u8 intel_dp_phy_voltage_max(struct intel_dp *intel_dp, |