[PATCH v3 0/6] add fixes to pass DP Link Layer compliance test cases

[PATCH v3 0/6] add fixes to pass DP Link Layer compliance test cases

[Kuogee Hsieh]

add fixes to pass DP Link Layer compliance test cases

Kuogee Hsieh (6):
  drm/msm/dp: use dp_ctrl_off_link_stream during PHY compliance test run
  drm/msm/dp: reduce link rate if failed at link training 1
  drm/msm/dp: reset aux controller after dp_aux_cmd_fifo_tx() failed.
  drm/msm/dp: replug event is converted into an unplug followed by an
    plug events
  drm/msm/dp: return correct edid checksum after corrupted edid checksum
    read
  drm/msm/dp: do not end dp link training until video is ready

 drivers/gpu/drm/msm/dp/dp_aux.c     |   3 +
 drivers/gpu/drm/msm/dp/dp_ctrl.c    | 137 +++++++++++++++++++++++-------------
 drivers/gpu/drm/msm/dp/dp_display.c |  14 ++--
 drivers/gpu/drm/msm/dp/dp_panel.c   |   9 ++-
 4 files changed, 102 insertions(+), 61 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v3 1/6] drm/msm/dp: use dp_ctrl_off_link_stream during PHY compliance test run

[Kuogee Hsieh]

DP cable should always connect to DPU during the entire PHY compliance
testing run. Since DP PHY compliance test is executed at irq_hpd event
context, dp_ctrl_off_link_stream() should be used instead of dp_ctrl_off().
dp_ctrl_off() is used for unplug event which is triggered when DP cable is
dis connected.

Changes in V2:
-- add fixes statement

Fixes: f21c8a276c2d ("drm/msm/dp: handle irq_hpd with sink_count = 0 correctly")

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index caf71fa..27fb0f0 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1530,7 +1530,7 @@ static int dp_ctrl_process_phy_test_request(struct dp_ctrl_private *ctrl)
 	 * running. Add the global reset just before disabling the
 	 * link clocks and core clocks.
 	 */
-	ret = dp_ctrl_off(&ctrl->dp_ctrl);
+	ret = dp_ctrl_off_link_stream(&ctrl->dp_ctrl);
 	if (ret) {
 		DRM_ERROR("failed to disable DP controller\n");
 		return ret;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v3 2/6] drm/msm/dp: reduce link rate if failed at link training 1

[Kuogee Hsieh]

Reduce link rate and re start link training if link training 1
failed due to loss of clock recovery done to fix Link Layer
CTS case 4.3.1.7.  Also only update voltage and pre-emphasis
swing level after link training started to fix Link Layer CTS
case 4.3.1.6.

Changes in V2:
-- replaced cr_status with link_status[DP_LINK_STATUS_SIZE]
-- replaced dp_ctrl_any_lane_cr_done() with dp_ctrl_colco_recovery_any_ok()
-- replaced dp_ctrl_any_ane_cr_lose() with !drm_dp_clock_recovery_ok()

Changes in V3:
-- return failed if lane_count <= 1

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c | 79 +++++++++++++++++++++++-----------------
 1 file changed, 45 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 27fb0f0..0002805 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -83,13 +83,6 @@ struct dp_ctrl_private {
 	struct completion video_comp;
 };
 
-struct dp_cr_status {
-	u8 lane_0_1;
-	u8 lane_2_3;
-};
-
-#define DP_LANE0_1_CR_DONE	0x11
-
 static int dp_aux_link_configure(struct drm_dp_aux *aux,
 					struct dp_link_info *link)
 {
@@ -1080,7 +1073,7 @@ static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl,
 }
 
 static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
-		struct dp_cr_status *cr, int *training_step)
+			int *training_step)
 {
 	int tries, old_v_level, ret = 0;
 	u8 link_status[DP_LINK_STATUS_SIZE];
@@ -1109,9 +1102,6 @@ static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
 		if (ret)
 			return ret;
 
-		cr->lane_0_1 = link_status[0];
-		cr->lane_2_3 = link_status[1];
-
 		if (drm_dp_clock_recovery_ok(link_status,
 			ctrl->link->link_params.num_lanes)) {
 			return 0;
@@ -1188,7 +1178,7 @@ static void dp_ctrl_clear_training_pattern(struct dp_ctrl_private *ctrl)
 }
 
 static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl,
-		struct dp_cr_status *cr, int *training_step)
+			int *training_step)
 {
 	int tries = 0, ret = 0;
 	char pattern;
@@ -1204,10 +1194,6 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl,
 	else
 		pattern = DP_TRAINING_PATTERN_2;
 
-	ret = dp_ctrl_update_vx_px(ctrl);
-	if (ret)
-		return ret;
-
 	ret = dp_catalog_ctrl_set_pattern(ctrl->catalog, pattern);
 	if (ret)
 		return ret;
@@ -1220,8 +1206,6 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl,
 		ret = dp_ctrl_read_link_status(ctrl, link_status);
 		if (ret)
 			return ret;
-		cr->lane_0_1 = link_status[0];
-		cr->lane_2_3 = link_status[1];
 
 		if (drm_dp_channel_eq_ok(link_status,
 			ctrl->link->link_params.num_lanes)) {
@@ -1241,7 +1225,7 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl,
 static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl);
 
 static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl,
-		struct dp_cr_status *cr, int *training_step)
+			int *training_step)
 {
 	int ret = 0;
 	u8 encoding = DP_SET_ANSI_8B10B;
@@ -1257,7 +1241,7 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl,
 	drm_dp_dpcd_write(ctrl->aux, DP_MAIN_LINK_CHANNEL_CODING_SET,
 				&encoding, 1);
 
-	ret = dp_ctrl_link_train_1(ctrl, cr, training_step);
+	ret = dp_ctrl_link_train_1(ctrl, training_step);
 	if (ret) {
 		DRM_ERROR("link training #1 failed. ret=%d\n", ret);
 		goto end;
@@ -1266,7 +1250,7 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl,
 	/* print success info as this is a result of user initiated action */
 	DRM_DEBUG_DP("link training #1 successful\n");
 
-	ret = dp_ctrl_link_train_2(ctrl, cr, training_step);
+	ret = dp_ctrl_link_train_2(ctrl, training_step);
 	if (ret) {
 		DRM_ERROR("link training #2 failed. ret=%d\n", ret);
 		goto end;
@@ -1282,7 +1266,7 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl,
 }
 
 static int dp_ctrl_setup_main_link(struct dp_ctrl_private *ctrl,
-		struct dp_cr_status *cr, int *training_step)
+			int *training_step)
 {
 	int ret = 0;
 
@@ -1297,7 +1281,7 @@ static int dp_ctrl_setup_main_link(struct dp_ctrl_private *ctrl,
 	 * a link training pattern, we have to first do soft reset.
 	 */
 
-	ret = dp_ctrl_link_train(ctrl, cr, training_step);
+	ret = dp_ctrl_link_train(ctrl, training_step);
 
 	return ret;
 }
@@ -1496,14 +1480,13 @@ static int dp_ctrl_deinitialize_mainlink(struct dp_ctrl_private *ctrl)
 static int dp_ctrl_link_maintenance(struct dp_ctrl_private *ctrl)
 {
 	int ret = 0;
-	struct dp_cr_status cr;
 	int training_step = DP_TRAINING_NONE;
 
 	dp_ctrl_push_idle(&ctrl->dp_ctrl);
 
 	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
 
-	ret = dp_ctrl_setup_main_link(ctrl, &cr, &training_step);
+	ret = dp_ctrl_setup_main_link(ctrl, &training_step);
 	if (ret)
 		goto end;
 
@@ -1634,6 +1617,25 @@ void dp_ctrl_handle_sink_request(struct dp_ctrl *dp_ctrl)
 	}
 }
 
+static bool dp_ctrl_clock_recovery_any_ok(
+			const u8 link_status[DP_LINK_STATUS_SIZE],
+			int lane_count)
+{
+	int reduced_cnt;
+
+	if (lane_count <= 1)
+		return false;
+
+	/*
+	 * only interested in the lane number after reduced
+	 * lane_count = 4, then only interested in 2 lanes
+	 * lane_count = 2, then only interested in 1 lane
+	 */
+	reduced_cnt = lane_count >> 1;
+
+	return drm_dp_clock_recovery_ok(link_status, reduced_cnt);
+}
+
 int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 {
 	int rc = 0;
@@ -1641,7 +1643,8 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 	u32 rate = 0;
 	int link_train_max_retries = 5;
 	u32 const phy_cts_pixel_clk_khz = 148500;
-	struct dp_cr_status cr;
+	u8 cr_status[2];
+	u8 link_status[DP_LINK_STATUS_SIZE];
 	unsigned int training_step;
 
 	if (!dp_ctrl)
@@ -1681,19 +1684,21 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 		}
 
 		training_step = DP_TRAINING_NONE;
-		rc = dp_ctrl_setup_main_link(ctrl, &cr, &training_step);
+		rc = dp_ctrl_setup_main_link(ctrl, &training_step);
 		if (rc == 0) {
 			/* training completed successfully */
 			break;
 		} else if (training_step == DP_TRAINING_1) {
 			/* link train_1 failed */
-			if (!dp_catalog_link_is_connected(ctrl->catalog)) {
+			if (!dp_catalog_link_is_connected(ctrl->catalog))
 				break;
-			}
+
+			dp_ctrl_read_link_status(ctrl, link_status);
 
 			rc = dp_ctrl_link_rate_down_shift(ctrl);
 			if (rc < 0) { /* already in RBR = 1.6G */
-				if (cr.lane_0_1 & DP_LANE0_1_CR_DONE) {
+				if (dp_ctrl_clock_recovery_any_ok(link_status,
+					ctrl->link->link_params.num_lanes)) {
 					/*
 					 * some lanes are ready,
 					 * reduce lane number
@@ -1709,12 +1714,18 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 				}
 			}
 		} else if (training_step == DP_TRAINING_2) {
-			/* link train_2 failed, lower lane rate */
-			if (!dp_catalog_link_is_connected(ctrl->catalog)) {
+			/* link train_2 failed */
+			if (!dp_catalog_link_is_connected(ctrl->catalog))
 				break;
-			}
 
-			rc = dp_ctrl_link_lane_down_shift(ctrl);
+			dp_ctrl_read_link_status(ctrl, link_status);
+
+			if (!drm_dp_clock_recovery_ok(link_status,
+					ctrl->link->link_params.num_lanes))
+				rc = dp_ctrl_link_rate_down_shift(ctrl);
+			else
+				rc = dp_ctrl_link_lane_down_shift(ctrl);
+
 			if (rc < 0) {
 				/* end with failure */
 				break; /* lane == 1 already */
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 2/6] drm/msm/dp: reduce link rate if failed at link training 1

[Stephen Boyd]

Quoting Kuogee Hsieh (2021-08-05 13:44:51)
> Reduce link rate and re start link training if link training 1
> failed due to loss of clock recovery done to fix Link Layer
> CTS case 4.3.1.7.  Also only update voltage and pre-emphasis
> swing level after link training started to fix Link Layer CTS
> case 4.3.1.6.
>
> Changes in V2:
> -- replaced cr_status with link_status[DP_LINK_STATUS_SIZE]
> -- replaced dp_ctrl_any_lane_cr_done() with dp_ctrl_colco_recovery_any_ok()
> -- replaced dp_ctrl_any_ane_cr_lose() with !drm_dp_clock_recovery_ok()
>
> Changes in V3:
> -- return failed if lane_count <= 1
>
> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

[PATCH v3 3/6] drm/msm/dp: reset aux controller after dp_aux_cmd_fifo_tx() failed.

[Kuogee Hsieh]

Aux hardware calibration sequence requires resetting the aux controller
in order for the new setting to take effect. However resetting the AUX
controller will also clear HPD interrupt status which may accidentally
cause pending unplug interrupt to get lost. Therefore reset aux
controller only when link is in connection state when dp_aux_cmd_fifo_tx()
fail. This fixes Link Layer CTS cases 4.2.1.1 and 4.2.1.2.

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/gpu/drm/msm/dp/dp_aux.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index 4a3293b..eb40d84 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -353,6 +353,9 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 			if (!(aux->retry_cnt % MAX_AUX_RETRIES))
 				dp_catalog_aux_update_cfg(aux->catalog);
 		}
+		/* reset aux if link is in connected state */
+		if (dp_catalog_link_is_connected(aux->catalog))
+			dp_catalog_aux_reset(aux->catalog);
 	} else {
 		aux->retry_cnt = 0;
 		switch (aux->aux_error_num) {
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v3 4/6] drm/msm/dp: replug event is converted into an unplug followed by an plug events

[Kuogee Hsieh]

Remove special handling of replug interrupt and instead treat replug event
as a sequential unplug followed by a plugin event. This is needed to meet
the requirements of DP Link Layer CTS test case 4.2.1.3.

Changes in V2:
-- add fixes statement

Changes in V3:
-- delete EV_HPD_REPLUG_INT

Fixes: f21c8a276c2d ("drm/msm/dp: handle irq_hpd with sink_count = 0 correctly")

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 78c5301..aa96272 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -55,7 +55,6 @@ enum {
 	EV_HPD_INIT_SETUP,
 	EV_HPD_PLUG_INT,
 	EV_IRQ_HPD_INT,
-	EV_HPD_REPLUG_INT,
 	EV_HPD_UNPLUG_INT,
 	EV_USER_NOTIFICATION,
 	EV_CONNECT_PENDING_TIMEOUT,
@@ -1146,9 +1145,6 @@ static int hpd_event_thread(void *data)
 		case EV_IRQ_HPD_INT:
 			dp_irq_hpd_handle(dp_priv, todo->data);
 			break;
-		case EV_HPD_REPLUG_INT:
-			/* do nothing */
-			break;
 		case EV_USER_NOTIFICATION:
 			dp_display_send_hpd_notification(dp_priv,
 						todo->data);
@@ -1192,10 +1188,8 @@ static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
 
 	if (hpd_isr_status & 0x0F) {
 		/* hpd related interrupts */
-		if (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK ||
-			hpd_isr_status & DP_DP_HPD_REPLUG_INT_MASK) {
+		if (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK)
 			dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
-		}
 
 		if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) {
 			/* stop sentinel connect pending checking */
@@ -1203,8 +1197,10 @@ static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
 			dp_add_event(dp, EV_IRQ_HPD_INT, 0, 0);
 		}
 
-		if (hpd_isr_status & DP_DP_HPD_REPLUG_INT_MASK)
-			dp_add_event(dp, EV_HPD_REPLUG_INT, 0, 0);
+		if (hpd_isr_status & DP_DP_HPD_REPLUG_INT_MASK) {
+			dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
+			dp_add_event(dp, EV_HPD_PLUG_INT, 0, 3);
+		}
 
 		if (hpd_isr_status & DP_DP_HPD_UNPLUG_INT_MASK)
 			dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 4/6] drm/msm/dp: replug event is converted into an unplug followed by an plug events

[Stephen Boyd]

Quoting Kuogee Hsieh (2021-08-05 13:44:53)
> Remove special handling of replug interrupt and instead treat replug event
> as a sequential unplug followed by a plugin event. This is needed to meet
> the requirements of DP Link Layer CTS test case 4.2.1.3.
>
> Changes in V2:
> -- add fixes statement
>
> Changes in V3:
> -- delete EV_HPD_REPLUG_INT
>
> Fixes: f21c8a276c2d ("drm/msm/dp: handle irq_hpd with sink_count = 0 correctly")
>
> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

[PATCH v3 5/6] drm/msm/dp: return correct edid checksum after corrupted edid checksum read

[Kuogee Hsieh]

Response with correct edid checksum saved at connector after corrupted edid
checksum read. This fixes Link Layer CTS cases 4.2.2.3, 4.2.2.6.

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_panel.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 88196f7..0fdb551 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -271,7 +271,7 @@ static u8 dp_panel_get_edid_checksum(struct edid *edid)
 {
 	struct edid *last_block;
 	u8 *raw_edid;
-	bool is_edid_corrupt;
+	bool is_edid_corrupt = false;
 
 	if (!edid) {
 		DRM_ERROR("invalid edid input\n");
@@ -303,7 +303,12 @@ void dp_panel_handle_sink_request(struct dp_panel *dp_panel)
 	panel = container_of(dp_panel, struct dp_panel_private, dp_panel);
 
 	if (panel->link->sink_request & DP_TEST_LINK_EDID_READ) {
-		u8 checksum = dp_panel_get_edid_checksum(dp_panel->edid);
+		u8 checksum;
+
+		if (dp_panel->edid)
+			checksum = dp_panel_get_edid_checksum(dp_panel->edid);
+		else
+			checksum = dp_panel->connector->real_edid_checksum;
 
 		dp_link_send_edid_checksum(panel->link, checksum);
 		dp_link_send_test_response(panel->link);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 5/6] drm/msm/dp: return correct edid checksum after corrupted edid checksum read

[Stephen Boyd]

Quoting Kuogee Hsieh (2021-08-05 13:44:54)
> Response with correct edid checksum saved at connector after corrupted edid
> checksum read. This fixes Link Layer CTS cases 4.2.2.3, 4.2.2.6.
>
> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

[PATCH v3 6/6] drm/msm/dp: do not end dp link training until video is ready

[Kuogee Hsieh]

Initialize both pre-emphasis and voltage swing level to 0 before
start link training and do not end link training until video is
ready to reduce the period between end of link training and video
start to meet Link Layer CTS requirement.  Some dongle main link
symbol may become unlocked again if host did not end link training
soon enough after completion of link training 2. Host have to re
train main link if loss of symbol locked detected before end link
training so that the coming video stream can be transmitted to sink
properly. This fixes Link Layer CTS cases 4.3.2.1, 4.3.2.2, 4.3.2.3
and 4.3.2.4.

Changes in v3:
-- merge retrain link if loss of symbol locked happen into this patch
-- replace dp_ctrl_loss_symbol_lock() with dp_ctrl_channel_eq_ok()

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c | 56 +++++++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 0002805..ffed523 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1484,6 +1484,9 @@ static int dp_ctrl_link_maintenance(struct dp_ctrl_private *ctrl)
 
 	dp_ctrl_push_idle(&ctrl->dp_ctrl);
 
+	ctrl->link->phy_params.p_level = 0;
+	ctrl->link->phy_params.v_level = 0;
+
 	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
 
 	ret = dp_ctrl_setup_main_link(ctrl, &training_step);
@@ -1636,6 +1639,16 @@ static bool dp_ctrl_clock_recovery_any_ok(
 	return drm_dp_clock_recovery_ok(link_status, reduced_cnt);
 }
 
+static bool dp_ctrl_channel_eq_ok(struct dp_ctrl_private *ctrl)
+{
+	u8 link_status[DP_LINK_STATUS_SIZE];
+	int num_lanes = ctrl->link->link_params.num_lanes;
+
+	dp_ctrl_read_link_status(ctrl, link_status);
+
+	return drm_dp_channel_eq_ok(link_status, num_lanes);
+}
+
 int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 {
 	int rc = 0;
@@ -1671,6 +1684,9 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 		ctrl->link->link_params.rate,
 		ctrl->link->link_params.num_lanes, ctrl->dp_ctrl.pixel_rate);
 
+	ctrl->link->phy_params.p_level = 0;
+	ctrl->link->phy_params.v_level = 0;
+
 	rc = dp_ctrl_enable_mainlink_clocks(ctrl);
 	if (rc)
 		return rc;
@@ -1736,17 +1752,19 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 	if (ctrl->link->sink_request & DP_TEST_LINK_PHY_TEST_PATTERN)
 		return rc;
 
-	/* stop txing train pattern */
-	dp_ctrl_clear_training_pattern(ctrl);
+	if (rc == 0) {  /* link train successfully */
+		/*
+		 * do not stop train pattern here
+		 * stop link training at on_stream
+		 * to pass compliance test
+		 */
+	} else  {
+		/*
+		 * link training failed
+		 * end txing train pattern here
+		 */
+		dp_ctrl_clear_training_pattern(ctrl);
 
-	/*
-	 * keep transmitting idle pattern until video ready
-	 * to avoid main link from loss of sync
-	 */
-	if (rc == 0)  /* link train successfully */
-		dp_ctrl_push_idle(dp_ctrl);
-	else  {
-		/* link training failed */
 		dp_ctrl_deinitialize_mainlink(ctrl);
 		rc = -ECONNRESET;
 	}
@@ -1754,9 +1772,15 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 	return rc;
 }
 
+static int dp_ctrl_link_retrain(struct dp_ctrl_private *ctrl)
+{
+	int training_step = DP_TRAINING_NONE;
+
+	return dp_ctrl_setup_main_link(ctrl, &training_step);
+}
+
 int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
 {
-	u32 rate = 0;
 	int ret = 0;
 	bool mainlink_ready = false;
 	struct dp_ctrl_private *ctrl;
@@ -1766,10 +1790,6 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
 
 	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
 
-	rate = ctrl->panel->link_info.rate;
-
-	ctrl->link->link_params.rate = rate;
-	ctrl->link->link_params.num_lanes = ctrl->panel->link_info.num_lanes;
 	ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
 
 	DRM_DEBUG_DP("rate=%d, num_lanes=%d, pixel_rate=%d\n",
@@ -1784,6 +1804,12 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
 		}
 	}
 
+	if (!dp_ctrl_channel_eq_ok(ctrl))
+		dp_ctrl_link_retrain(ctrl);
+
+	/* stop txing train pattern to end link training */
+	dp_ctrl_clear_training_pattern(ctrl);
+
 	ret = dp_ctrl_enable_stream_clocks(ctrl);
 	if (ret) {
 		DRM_ERROR("Failed to start pixel clocks. ret=%d\n", ret);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 6/6] drm/msm/dp: do not end dp link training until video is ready

[Stephen Boyd]

Quoting Kuogee Hsieh (2021-08-05 13:44:55)
> Initialize both pre-emphasis and voltage swing level to 0 before
> start link training and do not end link training until video is
> ready to reduce the period between end of link training and video
> start to meet Link Layer CTS requirement.  Some dongle main link
> symbol may become unlocked again if host did not end link training
> soon enough after completion of link training 2. Host have to re
> train main link if loss of symbol locked detected before end link
> training so that the coming video stream can be transmitted to sink
> properly. This fixes Link Layer CTS cases 4.3.2.1, 4.3.2.2, 4.3.2.3
> and 4.3.2.4.
>
> Changes in v3:
> -- merge retrain link if loss of symbol locked happen into this patch
> -- replace dp_ctrl_loss_symbol_lock() with dp_ctrl_channel_eq_ok()
>
> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

Re: [PATCH v3 0/6] add fixes to pass DP Link Layer compliance test cases

[Stephen Boyd]

Quoting Kuogee Hsieh (2021-08-05 13:44:49)
> add fixes to pass DP Link Layer compliance test cases
>
> Kuogee Hsieh (6):
>   drm/msm/dp: use dp_ctrl_off_link_stream during PHY compliance test run
>   drm/msm/dp: reduce link rate if failed at link training 1
>   drm/msm/dp: reset aux controller after dp_aux_cmd_fifo_tx() failed.
>   drm/msm/dp: replug event is converted into an unplug followed by an
>     plug events
>   drm/msm/dp: return correct edid checksum after corrupted edid checksum
>     read
>   drm/msm/dp: do not end dp link training until video is ready

I'm still able to use my Apple dongle with these patches so

Tested-by: Stephen Boyd <swboyd@chromium.org>

Re: [PATCH v3 0/6] add fixes to pass DP Link Layer compliance test cases

[Jani Nikula]

On Thu, 05 Aug 2021, Kuogee Hsieh <khsieh@codeaurora.org> wrote:
> add fixes to pass DP Link Layer compliance test cases

Nitpick, please also include the approriate subject prefix to the cover
letter, e.g. "drm/msm" or "drm/msm/dp". Helps with mail filtering. :)

BR,
Jani.

>
> Kuogee Hsieh (6):
>   drm/msm/dp: use dp_ctrl_off_link_stream during PHY compliance test run
>   drm/msm/dp: reduce link rate if failed at link training 1
>   drm/msm/dp: reset aux controller after dp_aux_cmd_fifo_tx() failed.
>   drm/msm/dp: replug event is converted into an unplug followed by an
>     plug events
>   drm/msm/dp: return correct edid checksum after corrupted edid checksum
>     read
>   drm/msm/dp: do not end dp link training until video is ready
>
>  drivers/gpu/drm/msm/dp/dp_aux.c     |   3 +
>  drivers/gpu/drm/msm/dp/dp_ctrl.c    | 137 +++++++++++++++++++++++-------------
>  drivers/gpu/drm/msm/dp/dp_display.c |  14 ++--
>  drivers/gpu/drm/msm/dp/dp_panel.c   |   9 ++-
>  4 files changed, 102 insertions(+), 61 deletions(-)

-- 
Jani Nikula, Intel Open Source Graphics Center