[Intel-gfx] [PATCH] drm/i915/dp: do not write DP_TRAINING_PATTERN_SET all the time
Jani Nikula
jani.nikula at intel.com
Fri Sep 27 14:10:44 CEST 2013
Neither the DP spec nor the compliance test spec state or imply that we
should write the DP_TRAINING_PATTERN_SET at every voltage swing and
pre-emphasis change. Indeed we probably shouldn't. So don't.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49402
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
I haven't tested this much, but it fixes the Zotac DP -> dual-hdmi
dongle for me.
---
drivers/gpu/drm/i915/intel_dp.c | 129 ++++++++++++++++++++++++++-------------
1 file changed, 87 insertions(+), 42 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 95a3159..ab805d3 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2313,7 +2313,7 @@ intel_dp_set_signal_levels(struct intel_dp *intel_dp, uint32_t *DP)
static bool
intel_dp_set_link_train(struct intel_dp *intel_dp,
- uint32_t dp_reg_value,
+ uint32_t *DP,
uint8_t dp_train_pat)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -2349,50 +2349,51 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
I915_WRITE(DP_TP_CTL(port), temp);
} else if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || port != PORT_A)) {
- dp_reg_value &= ~DP_LINK_TRAIN_MASK_CPT;
+ *DP &= ~DP_LINK_TRAIN_MASK_CPT;
switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
case DP_TRAINING_PATTERN_DISABLE:
- dp_reg_value |= DP_LINK_TRAIN_OFF_CPT;
+ *DP |= DP_LINK_TRAIN_OFF_CPT;
break;
case DP_TRAINING_PATTERN_1:
- dp_reg_value |= DP_LINK_TRAIN_PAT_1_CPT;
+ *DP |= DP_LINK_TRAIN_PAT_1_CPT;
break;
case DP_TRAINING_PATTERN_2:
- dp_reg_value |= DP_LINK_TRAIN_PAT_2_CPT;
+ *DP |= DP_LINK_TRAIN_PAT_2_CPT;
break;
case DP_TRAINING_PATTERN_3:
DRM_ERROR("DP training pattern 3 not supported\n");
- dp_reg_value |= DP_LINK_TRAIN_PAT_2_CPT;
+ *DP |= DP_LINK_TRAIN_PAT_2_CPT;
break;
}
} else {
- dp_reg_value &= ~DP_LINK_TRAIN_MASK;
+ *DP &= ~DP_LINK_TRAIN_MASK;
switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
case DP_TRAINING_PATTERN_DISABLE:
- dp_reg_value |= DP_LINK_TRAIN_OFF;
+ *DP |= DP_LINK_TRAIN_OFF;
break;
case DP_TRAINING_PATTERN_1:
- dp_reg_value |= DP_LINK_TRAIN_PAT_1;
+ *DP |= DP_LINK_TRAIN_PAT_1;
break;
case DP_TRAINING_PATTERN_2:
- dp_reg_value |= DP_LINK_TRAIN_PAT_2;
+ *DP |= DP_LINK_TRAIN_PAT_2;
break;
case DP_TRAINING_PATTERN_3:
DRM_ERROR("DP training pattern 3 not supported\n");
- dp_reg_value |= DP_LINK_TRAIN_PAT_2;
+ *DP |= DP_LINK_TRAIN_PAT_2;
break;
}
}
- I915_WRITE(intel_dp->output_reg, dp_reg_value);
+ I915_WRITE(intel_dp->output_reg, *DP);
POSTING_READ(intel_dp->output_reg);
- intel_dp_aux_native_write_1(intel_dp,
- DP_TRAINING_PATTERN_SET,
- dp_train_pat);
+ ret = intel_dp_aux_native_write_1(intel_dp, DP_TRAINING_PATTERN_SET,
+ dp_train_pat);
+ if (ret != 1)
+ return false;
if ((dp_train_pat & DP_TRAINING_PATTERN_MASK) !=
DP_TRAINING_PATTERN_DISABLE) {
@@ -2407,6 +2408,37 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
return true;
}
+static bool
+intel_dp_reset_link_train(struct intel_dp *intel_dp, uint32_t *DP,
+ uint8_t dp_train_pat)
+{
+ memset(intel_dp->train_set, 0, 4);
+ intel_dp_set_signal_levels(intel_dp, DP);
+ return intel_dp_set_link_train(intel_dp, DP, dp_train_pat);
+}
+
+static bool
+intel_dp_update_link_train(struct intel_dp *intel_dp, uint32_t *DP,
+ uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+ struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+ struct drm_device *dev = intel_dig_port->base.base.dev;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ int ret;
+
+ intel_get_adjust_train(intel_dp, link_status);
+ intel_dp_set_signal_levels(intel_dp, DP);
+
+ I915_WRITE(intel_dp->output_reg, *DP);
+ POSTING_READ(intel_dp->output_reg);
+
+ ret = intel_dp_aux_native_write(intel_dp, DP_TRAINING_LANE0_SET,
+ intel_dp->train_set,
+ intel_dp->lane_count);
+
+ return ret == intel_dp->lane_count;
+}
+
static void intel_dp_set_idle_link_train(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -2459,21 +2491,19 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
DP |= DP_PORT_EN;
- memset(intel_dp->train_set, 0, 4);
+ /* clock recovery */
+ if (!intel_dp_reset_link_train(intel_dp, &DP,
+ DP_TRAINING_PATTERN_1 |
+ DP_LINK_SCRAMBLING_DISABLE)) {
+ DRM_ERROR("failed to enable link training\n");
+ return;
+ }
+
voltage = 0xff;
voltage_tries = 0;
loop_tries = 0;
for (;;) {
- /* Use intel_dp->train_set[0] to set the voltage and pre emphasis values */
- uint8_t link_status[DP_LINK_STATUS_SIZE];
-
- intel_dp_set_signal_levels(intel_dp, &DP);
-
- /* Set training pattern 1 */
- if (!intel_dp_set_link_train(intel_dp, DP,
- DP_TRAINING_PATTERN_1 |
- DP_LINK_SCRAMBLING_DISABLE))
- break;
+ uint8_t link_status[DP_LINK_STATUS_SIZE];
drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
if (!intel_dp_get_link_status(intel_dp, link_status)) {
@@ -2496,7 +2526,9 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
DRM_DEBUG_KMS("too many full retries, give up\n");
break;
}
- memset(intel_dp->train_set, 0, 4);
+ intel_dp_reset_link_train(intel_dp, &DP,
+ DP_TRAINING_PATTERN_1 |
+ DP_LINK_SCRAMBLING_DISABLE);
voltage_tries = 0;
continue;
}
@@ -2512,8 +2544,11 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
voltage_tries = 0;
voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
- /* Compute new intel_dp->train_set as requested by target */
- intel_get_adjust_train(intel_dp, link_status);
+ /* Update training set as requested by target */
+ if (!intel_dp_update_link_train(intel_dp, &DP, link_status)) {
+ DRM_ERROR("failed to update link training\n");
+ break;
+ }
}
intel_dp->DP = DP;
@@ -2527,11 +2562,18 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
uint32_t DP = intel_dp->DP;
/* channel equalization */
+ if (!intel_dp_set_link_train(intel_dp, &DP,
+ DP_TRAINING_PATTERN_2 |
+ DP_LINK_SCRAMBLING_DISABLE)) {
+ DRM_ERROR("failed to start channel equalization\n");
+ return;
+ }
+
tries = 0;
cr_tries = 0;
channel_eq = false;
for (;;) {
- uint8_t link_status[DP_LINK_STATUS_SIZE];
+ uint8_t link_status[DP_LINK_STATUS_SIZE];
if (cr_tries > 5) {
DRM_ERROR("failed to train DP, aborting\n");
@@ -2539,21 +2581,18 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
break;
}
- intel_dp_set_signal_levels(intel_dp, &DP);
-
- /* channel eq pattern */
- if (!intel_dp_set_link_train(intel_dp, DP,
- DP_TRAINING_PATTERN_2 |
- DP_LINK_SCRAMBLING_DISABLE))
- break;
-
drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
- if (!intel_dp_get_link_status(intel_dp, link_status))
+ if (!intel_dp_get_link_status(intel_dp, link_status)) {
+ DRM_ERROR("failed to get link status\n");
break;
+ }
/* Make sure clock is still ok */
if (!drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) {
intel_dp_start_link_train(intel_dp);
+ intel_dp_set_link_train(intel_dp, &DP,
+ DP_TRAINING_PATTERN_2 |
+ DP_LINK_SCRAMBLING_DISABLE);
cr_tries++;
continue;
}
@@ -2567,13 +2606,19 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
if (tries > 5) {
intel_dp_link_down(intel_dp);
intel_dp_start_link_train(intel_dp);
+ intel_dp_set_link_train(intel_dp, &DP,
+ DP_TRAINING_PATTERN_2 |
+ DP_LINK_SCRAMBLING_DISABLE);
tries = 0;
cr_tries++;
continue;
}
- /* Compute new intel_dp->train_set as requested by target */
- intel_get_adjust_train(intel_dp, link_status);
+ /* Update training set as requested by target */
+ if (!intel_dp_update_link_train(intel_dp, &DP, link_status)) {
+ DRM_ERROR("failed to update link training\n");
+ break;
+ }
++tries;
}
@@ -2588,7 +2633,7 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
void intel_dp_stop_link_train(struct intel_dp *intel_dp)
{
- intel_dp_set_link_train(intel_dp, intel_dp->DP,
+ intel_dp_set_link_train(intel_dp, &intel_dp->DP,
DP_TRAINING_PATTERN_DISABLE);
}
--
1.7.9.5
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