From: Ville Syrjälä <ville.syrj...@linux.intel.com>
The docs give you the impression that the unique transition scale
value shouldn't matter when unique transition scale is enabled. But
as Imre found on BXT (and I verfied also on BSW) the value does
matter. So from now on just program the same value 0x9a always.
Cc: Imre Deak <imre.d...@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
drivers/gpu/drm/i915/intel_dp.c | 53 +++++++++++++++++++--------------------
drivers/gpu/drm/i915/intel_hdmi.c | 30 +++++++++++-----------
2 files changed, 42 insertions(+), 41 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index f424833..32d7e43 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3142,6 +3142,12 @@ static uint32_t vlv_signal_levels(struct intel_dp
*intel_dp)
return 0;
}
+static bool chv_need_uniq_trans_scale(uint8_t train_set)
+{
+ return (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) == DP_TRAIN_PRE_EMPH_LEVEL_0
&&
+ (train_set & DP_TRAIN_VOLTAGE_SWING_MASK) ==
DP_TRAIN_VOLTAGE_SWING_LEVEL_3;
+}
+
static uint32_t chv_signal_levels(struct intel_dp *intel_dp)
{
struct drm_device *dev = intel_dp_to_dev(intel_dp);
@@ -3260,41 +3266,34 @@ static uint32_t chv_signal_levels(struct intel_dp
*intel_dp)
/* Program swing margin */
for (i = 0; i < 4; i++) {
val = vlv_dpio_read(dev_priv, pipe, CHV_TX_DW2(ch, i));
+
val &= ~DPIO_SWING_MARGIN000_MASK;
val |= margin_reg_value << DPIO_SWING_MARGIN000_SHIFT;
+
+ /*
+ * Supposedly this value shouldn't matter when unique transition
+ * scale is disabled, but in fact it does matter. Let's just
+ * always program the same value and hope it's OK.
+ */
+ val &= ~(0xff << DPIO_UNIQ_TRANS_SCALE_SHIFT);
+ val |= 0x9a << DPIO_UNIQ_TRANS_SCALE_SHIFT;
+
vlv_dpio_write(dev_priv, pipe, CHV_TX_DW2(ch, i), val);
}
- /* Disable unique transition scale */
+ /*
+ * The document said it needs to set bit 27 for ch0 and bit 26
+ * for ch1. Might be a typo in the doc.
+ * For now, for this unique transition scale selection, set bit
+ * 27 for ch0 and ch1.
+ */
for (i = 0; i < 4; i++) {
val = vlv_dpio_read(dev_priv, pipe, CHV_TX_DW3(ch, i));
- val &= ~DPIO_TX_UNIQ_TRANS_SCALE_EN;
- vlv_dpio_write(dev_priv, pipe, CHV_TX_DW3(ch, i), val);
- }
-
- if (((train_set & DP_TRAIN_PRE_EMPHASIS_MASK)
- == DP_TRAIN_PRE_EMPH_LEVEL_0) &&
- ((train_set & DP_TRAIN_VOLTAGE_SWING_MASK)
- == DP_TRAIN_VOLTAGE_SWING_LEVEL_3)) {
-
- /*
- * The document said it needs to set bit 27 for ch0 and bit 26
- * for ch1. Might be a typo in the doc.
- * For now, for this unique transition scale selection, set bit
- * 27 for ch0 and ch1.
- */
- for (i = 0; i < 4; i++) {
- val = vlv_dpio_read(dev_priv, pipe, CHV_TX_DW3(ch, i));
+ if (chv_need_uniq_trans_scale(train_set))
val |= DPIO_TX_UNIQ_TRANS_SCALE_EN;
- vlv_dpio_write(dev_priv, pipe, CHV_TX_DW3(ch, i), val);
- }
-
- for (i = 0; i < 4; i++) {
- val = vlv_dpio_read(dev_priv, pipe, CHV_TX_DW2(ch, i));
- val &= ~(0xff << DPIO_UNIQ_TRANS_SCALE_SHIFT);
- val |= (0x9a << DPIO_UNIQ_TRANS_SCALE_SHIFT);
- vlv_dpio_write(dev_priv, pipe, CHV_TX_DW2(ch, i), val);
- }
+ else
+ val &= ~DPIO_TX_UNIQ_TRANS_SCALE_EN;
+ vlv_dpio_write(dev_priv, pipe, CHV_TX_DW3(ch, i), val);
}
/* Start swing calculation */
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
b/drivers/gpu/drm/i915/intel_hdmi.c
index ba845f7..9f79afb 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1846,31 +1846,33 @@ static void chv_hdmi_pre_enable(struct intel_encoder
*encoder)
for (i = 0; i < 4; i++) {
val = vlv_dpio_read(dev_priv, pipe, CHV_TX_DW2(ch, i));
+
val &= ~DPIO_SWING_MARGIN000_MASK;
val |= 102 << DPIO_SWING_MARGIN000_SHIFT;
+
+ /*
+ * Supposedly this value shouldn't matter when unique transition
+ * scale is disabled, but in fact it does matter. Let's just
+ * always program the same value and hope it's OK.
+ */
+ val &= ~(0xff << DPIO_UNIQ_TRANS_SCALE_SHIFT);
+ val |= 0x9a << DPIO_UNIQ_TRANS_SCALE_SHIFT;
+
vlv_dpio_write(dev_priv, pipe, CHV_TX_DW2(ch, i), val);
}
- /* Disable unique transition scale */
+ /*
+ * The document said it needs to set bit 27 for ch0 and bit 26
+ * for ch1. Might be a typo in the doc.
+ * For now, for this unique transition scale selection, set bit
+ * 27 for ch0 and ch1.
+ */
for (i = 0; i < 4; i++) {
val = vlv_dpio_read(dev_priv, pipe, CHV_TX_DW3(ch, i));
val &= ~DPIO_TX_UNIQ_TRANS_SCALE_EN;
vlv_dpio_write(dev_priv, pipe, CHV_TX_DW3(ch, i), val);
}
- /* Additional steps for 1200mV-0dB */
-#if 0
- val = vlv_dpio_read(dev_priv, pipe, VLV_TX_DW3(ch));
- if (ch)
- val |= DPIO_TX_UNIQ_TRANS_SCALE_CH1;
- else
- val |= DPIO_TX_UNIQ_TRANS_SCALE_CH0;
- vlv_dpio_write(dev_priv, pipe, VLV_TX_DW3(ch), val);
-
- vlv_dpio_write(dev_priv, pipe, VLV_TX_DW2(ch),
- vlv_dpio_read(dev_priv, pipe, VLV_TX_DW2(ch)) |
- (0x9a << DPIO_UNIQ_TRANS_SCALE_SHIFT));
-#endif
/* Start swing calculation */
val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW10(ch));
val |= DPIO_PCS_SWING_CALC_TX0_TX2 | DPIO_PCS_SWING_CALC_TX1_TX3;
