[Intel-gfx] [PATCH 7/7] drm/i915: Switch to LTTPR non-transparent mode link training
Imre Deak
imre.deak at intel.com
Tue Sep 22 12:51:06 UTC 2020
The DP Standard's recommendation is to use the LTTPR non-transparent
mode link training if LTTPRs are detected, so let's do this.
Besides power-saving, the advantages of this are that the maximum number
of LTTPRs can only be used in non-transparent mode (the limit is 5-8 in
transparent mode), and it provides a way to narrow down the reason for a
link training failure to a given link segment. Non-transparent mode is
probably also the mode that was tested the most by the industry.
The changes in this patchset:
- Pass the DP PHY that is currently link trained to all LT helpers, so
that these can access the correct LTTPR/DPRX DPCD registers.
- During LT take into account the LTTPR common lane rate/count and the
per LTTPR-PHY vswing/pre-emph limits.
- Switch to LTTPR non-transparent LT mode and train each link segment
according to the sequence in DP Standard v2.0 (complete CR/EQ for
each segment before continuing with the next segment).
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
.../drm/i915/display/intel_display_types.h | 1 +
drivers/gpu/drm/i915/display/intel_dp.c | 14 +-
.../drm/i915/display/intel_dp_link_training.c | 374 +++++++++++++++---
.../drm/i915/display/intel_dp_link_training.h | 10 +-
4 files changed, 327 insertions(+), 72 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index b04921eba73b..2fb4e9a6a316 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1281,6 +1281,7 @@ struct intel_dp {
u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
u8 lttpr_common_caps[DP_LTTPR_COMMON_CAP_SIZE];
+ u8 lttpr_phy_caps[DP_MAX_LTTPR_COUNT][DP_LTTPR_PHY_CAP_SIZE];
u8 fec_capable;
/* source rates */
int num_source_rates;
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index d88f327aa9ef..54ad31044eef 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -161,6 +161,7 @@ static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
162000, 270000, 540000, 810000
};
int i, max_rate;
+ int max_lttpr_rate;
if (drm_dp_has_quirk(&intel_dp->desc, 0,
DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS)) {
@@ -174,6 +175,9 @@ static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
}
max_rate = drm_dp_bw_code_to_link_rate(intel_dp->dpcd[DP_MAX_LINK_RATE]);
+ max_lttpr_rate = drm_dp_lttpr_max_link_rate(intel_dp->lttpr_common_caps);
+ if (max_lttpr_rate)
+ max_rate = min(max_rate, max_lttpr_rate);
for (i = 0; i < ARRAY_SIZE(dp_rates); i++) {
if (dp_rates[i] > max_rate)
@@ -219,6 +223,10 @@ static int intel_dp_max_common_lane_count(struct intel_dp *intel_dp)
int source_max = dig_port->max_lanes;
int sink_max = drm_dp_max_lane_count(intel_dp->dpcd);
int fia_max = intel_tc_port_fia_max_lane_count(dig_port);
+ int lttpr_max = drm_dp_lttpr_max_lane_count(intel_dp->lttpr_common_caps);
+
+ if (lttpr_max)
+ sink_max = min(sink_max, lttpr_max);
return min3(source_max, sink_max, fia_max);
}
@@ -5540,13 +5548,13 @@ void intel_dp_process_phy_request(struct intel_dp *intel_dp)
&intel_dp->compliance.test_data.phytest;
u8 link_status[DP_LINK_STATUS_SIZE];
- if (!intel_dp_get_link_status(intel_dp, link_status)) {
+ if (!intel_dp_get_link_status(intel_dp, DP_PHY_DPRX, link_status)) {
DRM_DEBUG_KMS("failed to get link status\n");
return;
}
/* retrieve vswing & pre-emphasis setting */
- intel_dp_get_adjust_train(intel_dp, link_status);
+ intel_dp_get_adjust_train(intel_dp, DP_PHY_DPRX, link_status);
intel_dp_autotest_phy_ddi_disable(intel_dp);
@@ -5701,7 +5709,7 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
if (intel_psr_enabled(intel_dp))
return false;
- if (!intel_dp_get_link_status(intel_dp, link_status))
+ if (!intel_dp_get_link_status(intel_dp, DP_PHY_DPRX, link_status))
return false;
/*
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 1485602659be..3aa685a9aa2a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -25,6 +25,8 @@
#include "intel_dp.h"
#include "intel_dp_link_training.h"
+#define DP_PHY_LTTPR(i) (DP_PHY_LTTPR1 + (i))
+
static void
intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE])
{
@@ -35,37 +37,140 @@ intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE])
}
/**
- * intel_dp_get_link_status - get the link status information for the DPRX
+ * intel_dp_get_link_status - get the link status information for a DP PHY
* @intel_dp: DP struct
+ * @dp_phy: the DP PHY to get the link status for
* @link_status: buffer to return the status in
*
- * Fetch the AUX DPCD registers for the DPRX link status.
+ * Fetch the AUX DPCD registers for the DPRX or an LTTPR PHY link status. The
+ * layout of the returned @link_status matches the DPCD register layout of the
+ * DPRX PHY link status.
*
* Returns true if the information was read successfully, false otherwise.
*/
bool
-intel_dp_get_link_status(struct intel_dp *intel_dp, u8 link_status[DP_LINK_STATUS_SIZE])
+intel_dp_get_link_status(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy,
+ u8 link_status[DP_LINK_STATUS_SIZE])
{
- return drm_dp_dpcd_read(&intel_dp->aux, DP_LANE0_1_STATUS, link_status,
- DP_LINK_STATUS_SIZE) == DP_LINK_STATUS_SIZE;
+ u8 lttpr_status[DP_LINK_STATUS_SIZE - 1];
+
+ if (dp_phy == DP_PHY_DPRX)
+ return drm_dp_dpcd_read(&intel_dp->aux,
+ DP_LANE0_1_STATUS,
+ link_status,
+ DP_LINK_STATUS_SIZE) == DP_LINK_STATUS_SIZE;
+
+ if (drm_dp_dpcd_read(&intel_dp->aux,
+ DP_LANE0_1_STATUS_PHY_REPEATER(dp_phy),
+ lttpr_status,
+ sizeof(lttpr_status)) != sizeof(lttpr_status))
+ return false;
+
+#define link_reg(reg) link_status[(reg) - DP_LANE0_1_STATUS]
+#define lttpr_reg(reg) lttpr_status[(reg) - DP_LANE0_1_STATUS_PHY_REPEATER1]
+
+ /* Convert the LTTPR to the sink PHY link status layout */
+ link_reg(DP_LANE0_1_STATUS) = lttpr_reg(DP_LANE0_1_STATUS_PHY_REPEATER1);
+ link_reg(DP_LANE2_3_STATUS) = lttpr_reg(DP_LANE2_3_STATUS_PHY_REPEATER1);
+ link_reg(DP_LANE_ALIGN_STATUS_UPDATED) =
+ lttpr_reg(DP_LANE_ALIGN_STATUS_UPDATED_PHY_REPEATER1);
+ link_reg(DP_SINK_STATUS) = 0;
+ link_reg(DP_ADJUST_REQUEST_LANE0_1) =
+ lttpr_reg(DP_ADJUST_REQUEST_LANE0_1_PHY_REPEATER1);
+ link_reg(DP_ADJUST_REQUEST_LANE2_3) =
+ lttpr_reg(DP_ADJUST_REQUEST_LANE2_3_PHY_REPEATER1);
+
+#undef link_reg
+#undef lttpr_reg
+
+ return true;
+}
+
+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 const char *intel_dp_phy_name(enum drm_dp_phy dp_phy,
+ char *buf, size_t buf_size)
+{
+ if (dp_phy == DP_PHY_DPRX)
+ snprintf(buf, buf_size, "DPRX");
+ else
+ snprintf(buf, buf_size, "LTTPR %d", dp_phy - DP_PHY_LTTPR1 + 1);
+
+ return buf;
+}
+
+static uint8_t *intel_dp_lttpr_phy_caps(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
+{
+ return &intel_dp->lttpr_phy_caps[dp_phy - DP_PHY_LTTPR1][0];
}
/**
- * intel_dp_read_lttpr_caps - read the LTTPR common capabilities
+ * intel_dp_read_lttpr_caps - read the LTTPR common and per-PHY capabilities
* @intel_dp: Intel DP struct
*
- * Read the LTTPR common capabilities.
+ * Read the LTTPR common capabilities and the PHY capabilities for all
+ * detected LTTPRs. In case of an LTTPR detection error or if the number of
+ * LTTPRs is more than is supported (8), fall back to the no-LTTPR,
+ * transparent mode link training mode.
*/
void intel_dp_read_lttpr_caps(struct intel_dp *intel_dp)
{
+ int lttpr_count;
+ int i;
+
if (drm_dp_read_lttpr_common_caps(&intel_dp->aux,
- intel_dp->lttpr_common_caps) < 0)
+ intel_dp->lttpr_common_caps) < 0) {
+ memset(intel_dp->lttpr_common_caps, 0,
+ sizeof(intel_dp->lttpr_common_caps));
return;
+ }
drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
"LTTPR common capabilities: %*ph\n",
(int)sizeof(intel_dp->lttpr_common_caps),
intel_dp->lttpr_common_caps);
+
+ lttpr_count = intel_dp_lttpr_count(intel_dp);
+ /*
+ * In case of unsupported number of LTTPRs fall-back to transparent
+ * link training mode, still taking into account any LTTPR common
+ * lane- rate/count limits.
+ */
+ if (lttpr_count <= 0)
+ return;
+
+ for (i = 0; i < lttpr_count; i++) {
+ enum drm_dp_phy dp_phy = DP_PHY_LTTPR(i);
+ uint8_t *phy_caps = intel_dp_lttpr_phy_caps(intel_dp, dp_phy);
+ char phy_name[10];
+
+ intel_dp_phy_name(dp_phy, phy_name, sizeof(phy_name));
+
+ if (drm_dp_read_lttpr_phy_caps(&intel_dp->aux, dp_phy, phy_caps) < 0) {
+ drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
+ "failed to read the PHY caps for %s\n",
+ phy_name);
+ continue;
+ }
+
+ drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
+ "%s PHY capabilities: %*ph\n",
+ phy_name,
+ (int)sizeof(intel_dp->lttpr_phy_caps[0]),
+ phy_caps);
+ }
}
static u8 dp_voltage_max(u8 preemph)
@@ -83,10 +188,78 @@ static u8 dp_voltage_max(u8 preemph)
}
}
+static u8 intel_dp_lttpr_voltage_max(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
+{
+ const uint8_t *phy_caps = intel_dp_lttpr_phy_caps(intel_dp, dp_phy);
+
+ if (drm_dp_lttpr_voltage_swing_level_3_supported(phy_caps))
+ return DP_TRAIN_VOLTAGE_SWING_LEVEL_3;
+ else
+ return DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
+}
+
+static u8 intel_dp_lttpr_preemph_max(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
+{
+ const uint8_t *phy_caps = intel_dp_lttpr_phy_caps(intel_dp, dp_phy);
+
+ if (drm_dp_lttpr_pre_emphasis_level_3_supported(phy_caps))
+ return DP_TRAIN_PRE_EMPH_LEVEL_3;
+ else
+ return DP_TRAIN_PRE_EMPH_LEVEL_2;
+}
+
+static u8 intel_dp_phy_voltage_max(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);
+ u8 voltage_max;
+
+ /*
+ * Get voltage_max from the DPTX_PHY (source or LTTPR) upstream from
+ * the DPRX_PHY we train.
+ */
+ if (lttpr_count == 0 || dp_phy == DP_PHY_LTTPR(lttpr_count - 1))
+ voltage_max = intel_dp->voltage_max(intel_dp);
+ else
+ voltage_max = intel_dp_lttpr_voltage_max(intel_dp, dp_phy + 1);
+
+ drm_WARN_ON_ONCE(&i915->drm,
+ voltage_max != DP_TRAIN_VOLTAGE_SWING_LEVEL_2 &&
+ voltage_max != DP_TRAIN_VOLTAGE_SWING_LEVEL_3);
+
+ return voltage_max;
+}
+
+static u8 intel_dp_phy_preemph_max(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);
+ u8 preemph_max;
+
+ /*
+ * Get preemph_max from the DPTX_PHY (source or LTTPR) upstream from
+ * the DPRX_PHY we train.
+ */
+ if (lttpr_count == 0 || dp_phy == DP_PHY_LTTPR(lttpr_count - 1))
+ preemph_max = intel_dp->preemph_max(intel_dp);
+ else
+ preemph_max = intel_dp_lttpr_preemph_max(intel_dp, dp_phy + 1);
+
+ drm_WARN_ON_ONCE(&i915->drm,
+ preemph_max != DP_TRAIN_PRE_EMPH_LEVEL_2 &&
+ preemph_max != DP_TRAIN_PRE_EMPH_LEVEL_3);
+
+ return preemph_max;
+}
+
void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy,
const u8 link_status[DP_LINK_STATUS_SIZE])
{
- struct drm_i915_private *i915 = dp_to_i915(intel_dp);
u8 v = 0;
u8 p = 0;
int lane;
@@ -98,21 +271,13 @@ void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
p = max(p, drm_dp_get_adjust_request_pre_emphasis(link_status, lane));
}
- preemph_max = intel_dp->preemph_max(intel_dp);
- drm_WARN_ON_ONCE(&i915->drm,
- preemph_max != DP_TRAIN_PRE_EMPH_LEVEL_2 &&
- preemph_max != DP_TRAIN_PRE_EMPH_LEVEL_3);
-
+ preemph_max = intel_dp_phy_preemph_max(intel_dp, dp_phy);
if (p >= preemph_max)
p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
v = min(v, dp_voltage_max(p));
- voltage_max = intel_dp->voltage_max(intel_dp);
- drm_WARN_ON_ONCE(&i915->drm,
- voltage_max != DP_TRAIN_VOLTAGE_SWING_LEVEL_2 &&
- voltage_max != DP_TRAIN_VOLTAGE_SWING_LEVEL_3);
-
+ voltage_max = intel_dp_phy_voltage_max(intel_dp, dp_phy);
if (v >= voltage_max)
v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
@@ -120,17 +285,24 @@ void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
intel_dp->train_set[lane] = v | p;
}
-static bool intel_dp_disable_dpcd_training_pattern(struct intel_dp *intel_dp)
+static bool intel_dp_disable_dpcd_training_pattern(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
{
+ int reg = dp_phy == DP_PHY_DPRX ?
+ DP_TRAINING_PATTERN_SET :
+ DP_TRAINING_PATTERN_SET_PHY_REPEATER(dp_phy);
u8 val = DP_TRAINING_PATTERN_DISABLE;
- return drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET, &val, 1) == 1;
+ return drm_dp_dpcd_write(&intel_dp->aux, reg, &val, 1) == 1;
}
static bool
-intel_dp_set_link_train(struct intel_dp *intel_dp,
+intel_dp_set_link_train(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
u8 dp_train_pat)
{
+ int reg = dp_phy == DP_PHY_DPRX ?
+ DP_TRAINING_PATTERN_SET :
+ DP_TRAINING_PATTERN_SET_PHY_REPEATER(dp_phy);
u8 buf[sizeof(intel_dp->train_set) + 1];
int len;
@@ -139,34 +311,36 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
if ((dp_train_pat & ~DP_LINK_SCRAMBLING_DISABLE) ==
DP_TRAINING_PATTERN_DISABLE)
/* don't write DP_TRAINING_LANEx_SET on disable */
- return intel_dp_disable_dpcd_training_pattern(intel_dp);
+ return intel_dp_disable_dpcd_training_pattern(intel_dp, dp_phy);
buf[0] = dp_train_pat;
/* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */
memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count);
len = intel_dp->lane_count + 1;
- return drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
- buf, len) == len;
+ return drm_dp_dpcd_write(&intel_dp->aux, reg, buf, len) == len;
}
static bool
-intel_dp_reset_link_train(struct intel_dp *intel_dp,
+intel_dp_reset_link_train(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
u8 dp_train_pat)
{
memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set));
intel_dp_set_signal_levels(intel_dp);
- return intel_dp_set_link_train(intel_dp, dp_train_pat);
+ return intel_dp_set_link_train(intel_dp, dp_phy, dp_train_pat);
}
static bool
-intel_dp_update_link_train(struct intel_dp *intel_dp)
+intel_dp_update_link_train(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy)
{
+ int reg = dp_phy == DP_PHY_DPRX ?
+ DP_TRAINING_LANE0_SET :
+ DP_TRAINING_LANE0_SET_PHY_REPEATER(dp_phy);
int ret;
intel_dp_set_signal_levels(intel_dp);
- ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_LANE0_SET,
+ ret = drm_dp_dpcd_write(&intel_dp->aux, reg,
intel_dp->train_set, intel_dp->lane_count);
return ret == intel_dp->lane_count;
@@ -226,9 +400,22 @@ static void intel_dp_prepare_link_train(struct intel_dp *intel_dp)
intel_dp->DP |= DP_PORT_EN;
}
-/* Perform the link training clock recovery phase using training pattern 1. */
+static void intel_dp_link_training_clock_recovery_delay(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
+{
+ if (dp_phy == DP_PHY_DPRX)
+ drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
+ else
+ drm_dp_lttpr_link_train_clock_recovery_delay();
+}
+
+/*
+ * Perform the link training clock recovery phase on the given DP PHY using
+ * training pattern 1.
+ */
static bool
-intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
+intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
{
struct drm_i915_private *i915 = dp_to_i915(intel_dp);
u8 voltage;
@@ -236,7 +423,7 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
bool max_vswing_reached = false;
/* clock recovery */
- if (!intel_dp_reset_link_train(intel_dp,
+ if (!intel_dp_reset_link_train(intel_dp, dp_phy,
DP_TRAINING_PATTERN_1 |
DP_LINK_SCRAMBLING_DISABLE)) {
drm_err(&i915->drm, "failed to enable link training\n");
@@ -260,9 +447,9 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
for (cr_tries = 0; cr_tries < max_cr_tries; ++cr_tries) {
u8 link_status[DP_LINK_STATUS_SIZE];
- drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
+ intel_dp_link_training_clock_recovery_delay(intel_dp, dp_phy);
- if (!intel_dp_get_link_status(intel_dp, link_status)) {
+ if (!intel_dp_get_link_status(intel_dp, dp_phy, link_status)) {
drm_err(&i915->drm, "failed to get link status\n");
return false;
}
@@ -286,8 +473,8 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
/* Update training set as requested by target */
- intel_dp_get_adjust_train(intel_dp, link_status);
- if (!intel_dp_update_link_train(intel_dp)) {
+ intel_dp_get_adjust_train(intel_dp, dp_phy, link_status);
+ if (!intel_dp_update_link_train(intel_dp, dp_phy)) {
drm_err(&i915->drm,
"failed to update link training\n");
return false;
@@ -313,7 +500,8 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
* or for 1.4 devices that support it, 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)
+static u32 intel_dp_training_pattern(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
{
bool source_tps3, sink_tps3, source_tps4, sink_tps4;
@@ -322,9 +510,11 @@ static u32 intel_dp_training_pattern(struct intel_dp *intel_dp)
* for all downstream devices that support HBR3. There are no known eDP
* panels that support TPS4 as of Feb 2018 as per VESA eDP_v1.4b_E1
* specification.
+ * LTTPRs must support TPS4.
*/
source_tps4 = intel_dp_source_supports_hbr3(intel_dp);
- sink_tps4 = drm_dp_tps4_supported(intel_dp->dpcd);
+ sink_tps4 = dp_phy != DP_PHY_DPRX ||
+ drm_dp_tps4_supported(intel_dp->dpcd);
if (source_tps4 && sink_tps4) {
return DP_TRAINING_PATTERN_4;
} else if (intel_dp->link_rate == 810000) {
@@ -341,7 +531,8 @@ static u32 intel_dp_training_pattern(struct intel_dp *intel_dp)
* all sinks follow the spec.
*/
source_tps3 = intel_dp_source_supports_hbr2(intel_dp);
- sink_tps3 = drm_dp_tps3_supported(intel_dp->dpcd);
+ sink_tps3 = dp_phy != DP_PHY_DPRX ||
+ drm_dp_tps3_supported(intel_dp->dpcd);
if (source_tps3 && sink_tps3) {
return DP_TRAINING_PATTERN_3;
} else if (intel_dp->link_rate >= 540000) {
@@ -356,12 +547,27 @@ static u32 intel_dp_training_pattern(struct intel_dp *intel_dp)
return DP_TRAINING_PATTERN_2;
}
+static void
+intel_dp_link_training_channel_equalization_delay(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
+{
+ if (dp_phy == DP_PHY_DPRX) {
+ drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
+ } else {
+ const uint8_t *phy_caps = intel_dp_lttpr_phy_caps(intel_dp, dp_phy);
+
+ drm_dp_lttpr_link_train_channel_eq_delay(phy_caps);
+ }
+}
+
/*
- * Perform the link training channel equalization phase using one of training
- * pattern 2, 3 or 4 depending on the the source and sink capabilities.
+ * Perform the link training channel equalization phase on the given DP PHY
+ * using one of training pattern 2, 3 or 4 depending on the the source and
+ * sink capabilities.
*/
static bool
-intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
+intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp,
+ enum drm_dp_phy dp_phy)
{
struct drm_i915_private *i915 = dp_to_i915(intel_dp);
int tries;
@@ -369,22 +575,21 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
u8 link_status[DP_LINK_STATUS_SIZE];
bool channel_eq = false;
- training_pattern = intel_dp_training_pattern(intel_dp);
+ training_pattern = intel_dp_training_pattern(intel_dp, dp_phy);
/* Scrambling is disabled for TPS2/3 and enabled for TPS4 */
if (training_pattern != DP_TRAINING_PATTERN_4)
training_pattern |= DP_LINK_SCRAMBLING_DISABLE;
/* channel equalization */
- if (!intel_dp_set_link_train(intel_dp,
- training_pattern)) {
+ if (!intel_dp_set_link_train(intel_dp, dp_phy, training_pattern)) {
drm_err(&i915->drm, "failed to start channel equalization\n");
return false;
}
for (tries = 0; tries < 5; tries++) {
-
- drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
- if (!intel_dp_get_link_status(intel_dp, link_status)) {
+ intel_dp_link_training_channel_equalization_delay(intel_dp,
+ dp_phy);
+ if (!intel_dp_get_link_status(intel_dp, dp_phy, link_status)) {
drm_err(&i915->drm,
"failed to get link status\n");
break;
@@ -409,8 +614,8 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
}
/* Update training set as requested by target */
- intel_dp_get_adjust_train(intel_dp, link_status);
- if (!intel_dp_update_link_train(intel_dp)) {
+ intel_dp_get_adjust_train(intel_dp, dp_phy, link_status);
+ if (!intel_dp_update_link_train(intel_dp, dp_phy)) {
drm_err(&i915->drm,
"failed to update link training\n");
break;
@@ -424,8 +629,6 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
"Channel equalization failed 5 times\n");
}
- intel_dp_set_idle_link_train(intel_dp);
-
return channel_eq;
}
@@ -442,34 +645,33 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
void intel_dp_stop_link_train(struct intel_dp *intel_dp)
{
intel_dp->link_trained = true;
-
- intel_dp_set_link_train(intel_dp,
+ intel_dp_set_link_train(intel_dp, DP_PHY_DPRX,
DP_TRAINING_PATTERN_DISABLE);
}
static bool
-intel_dp_link_train(struct intel_dp *intel_dp)
+intel_dp_link_train_phy(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy)
{
struct intel_connector *intel_connector = intel_dp->attached_connector;
+ char phy_name[10];
bool ret = false;
- intel_dp_prepare_link_train(intel_dp);
-
- if (!intel_dp_link_training_clock_recovery(intel_dp))
+ if (!intel_dp_link_training_clock_recovery(intel_dp, dp_phy))
goto out;
- if (!intel_dp_link_training_channel_equalization(intel_dp))
+ if (!intel_dp_link_training_channel_equalization(intel_dp, dp_phy))
goto out;
ret = true;
out:
drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
- "[CONNECTOR:%d:%s] Link Training %s at Link Rate = %d, Lane count = %d",
+ "[CONNECTOR:%d:%s] Link Training %s at Link Rate = %d, Lane count = %d, at %s",
intel_connector->base.base.id,
intel_connector->base.name,
ret ? "passed" : "failed",
- intel_dp->link_rate, intel_dp->lane_count);
+ intel_dp->link_rate, intel_dp->lane_count,
+ intel_dp_phy_name(dp_phy, phy_name, sizeof(phy_name)));
return ret;
}
@@ -492,6 +694,33 @@ static void intel_dp_schedule_fallback_link_training(struct intel_dp *intel_dp)
schedule_work(&intel_connector->modeset_retry_work);
}
+/* Perform the link training on all LTTPRs and the DPRX on a link. */
+static bool
+intel_dp_link_train_all_phys(struct intel_dp *intel_dp, int lttpr_count)
+{
+ bool ret = true;
+ int i;
+
+ intel_dp_prepare_link_train(intel_dp);
+
+ for (i = lttpr_count - 1; i >= 0; i--) {
+ enum drm_dp_phy dp_phy = DP_PHY_LTTPR(i);
+
+ ret = intel_dp_link_train_phy(intel_dp, dp_phy);
+ intel_dp_disable_dpcd_training_pattern(intel_dp, dp_phy);
+
+ if (!ret)
+ break;
+ }
+
+ if (ret)
+ intel_dp_link_train_phy(intel_dp, DP_PHY_DPRX);
+
+ intel_dp_set_idle_link_train(intel_dp);
+
+ return ret;
+}
+
static bool
intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
{
@@ -501,10 +730,12 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
return drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) == 1;
}
-static void intel_dp_init_lttpr_mode(struct intel_dp *intel_dp)
+static int intel_dp_init_lttpr_mode(struct intel_dp *intel_dp)
{
+ int lttpr_count;
+
if (intel_dp_is_edp(intel_dp))
- return;
+ return 0;
/*
* TODO: the following re-reading of LTTPR caps can be removed
@@ -512,6 +743,19 @@ static void intel_dp_init_lttpr_mode(struct intel_dp *intel_dp)
*/
intel_dp_read_lttpr_caps(intel_dp);
intel_dp_set_lttpr_transparent_mode(intel_dp, true);
+
+ lttpr_count = intel_dp_lttpr_count(intel_dp);
+ if (lttpr_count) {
+ /*
+ * If we can't set non-transparent mode fall-back to
+ * transparent mode, still taking into account any LTTPR
+ * common lane rate and count limits.
+ */
+ if (!intel_dp_set_lttpr_transparent_mode(intel_dp, false))
+ lttpr_count = 0;
+ }
+
+ return lttpr_count;
}
/**
@@ -525,8 +769,8 @@ static void intel_dp_init_lttpr_mode(struct intel_dp *intel_dp)
*/
void intel_dp_start_link_train(struct intel_dp *intel_dp)
{
- intel_dp_init_lttpr_mode(intel_dp);
+ int lttpr_count = intel_dp_init_lttpr_mode(intel_dp);
- if (!intel_dp_link_train(intel_dp))
+ if (!intel_dp_link_train_all_phys(intel_dp, lttpr_count))
intel_dp_schedule_fallback_link_training(intel_dp);
}
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.h b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
index c0be3ff709a0..d0393b76ffc1 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
@@ -10,12 +10,14 @@
struct intel_dp;
-bool intel_dp_get_link_status(struct intel_dp *intel_dp,
- u8 link_status[DP_LINK_STATUS_SIZE]);
+bool
+intel_dp_get_link_status(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
+ u8 link_status[DP_LINK_STATUS_SIZE]);
void intel_dp_read_lttpr_caps(struct intel_dp *intel_dp);
-void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
- const u8 link_status[DP_LINK_STATUS_SIZE]);
+void
+intel_dp_get_adjust_train(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
+ const u8 link_status[DP_LINK_STATUS_SIZE]);
void intel_dp_start_link_train(struct intel_dp *intel_dp);
void intel_dp_stop_link_train(struct intel_dp *intel_dp);
--
2.17.1
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