Add per-lane abstraction for max vswing reached to make follow-up
cleaner, as this one reverses the conditions.
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nik...@intel.com>
---
.../drm/i915/display/intel_dp_link_training.c | 42 +++++++++++--------
1 file changed, 25 insertions(+), 17 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 1a943ae38a6b..d239d72bfcf2 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -515,29 +515,37 @@ intel_dp_update_link_train(struct intel_dp *intel_dp,
return ret == crtc_state->lane_count;
}
+/*
+ * FIXME: The DP spec is very confusing here, also the Link CTS spec seems to
+ * have self contradicting tests around this area.
+ *
+ * In lieu of better ideas let's just stop when we've reached the max supported
+ * vswing with its max pre-emphasis, which is either 2+1 or 3+0 depending on
+ * whether vswing level 3 is supported or not.
+ */
+static bool intel_dp_lane_max_vswing_reached(u8 train_set_lane)
+{
+ u8 v = (train_set_lane & DP_TRAIN_VOLTAGE_SWING_MASK) >>
+ DP_TRAIN_VOLTAGE_SWING_SHIFT;
+ u8 p = (train_set_lane & DP_TRAIN_PRE_EMPHASIS_MASK) >>
+ DP_TRAIN_PRE_EMPHASIS_SHIFT;
+
+ if (train_set_lane & DP_TRAIN_MAX_SWING_REACHED)
+ return true;
+
+ if (v + p == 3)
+ return true;
+
+ return false;
+}
+
static bool intel_dp_link_max_vswing_reached(struct intel_dp *intel_dp,
const struct intel_crtc_state
*crtc_state)
{
int lane;
- /*
- * FIXME: The DP spec is very confusing here, also the Link CTS
- * spec seems to have self contradicting tests around this area.
- *
- * In lieu of better ideas let's just stop when we've reached the
- * max supported vswing with its max pre-emphasis, which is either
- * 2+1 or 3+0 depending on whether vswing level 3 is supported or not.
- */
for (lane = 0; lane < crtc_state->lane_count; lane++) {
- u8 v = (intel_dp->train_set[lane] &
DP_TRAIN_VOLTAGE_SWING_MASK) >>
- DP_TRAIN_VOLTAGE_SWING_SHIFT;
- u8 p = (intel_dp->train_set[lane] & DP_TRAIN_PRE_EMPHASIS_MASK)
>>
- DP_TRAIN_PRE_EMPHASIS_SHIFT;
-
- if ((intel_dp->train_set[lane] & DP_TRAIN_MAX_SWING_REACHED) ==
0)
- return false;
-
- if (v + p != 3)
+ if
(!intel_dp_lane_max_vswing_reached(intel_dp->train_set[lane]))
return false;
}
--
2.30.2
