[PATCH] drm/msm/dp: force link training for display resolution change

[Kuogee Hsieh <quic_khsieh@quicinc.com>]

During display resolution changes display have to be disabled first
followed by display enable with new resolution. This patch force
main link always be retrained during display enable procedure to
simplify implementation instead of manually kicking of irq_hpd
handle.

Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c    |  6 +++---
 drivers/gpu/drm/msm/dp/dp_ctrl.h    |  2 +-
 drivers/gpu/drm/msm/dp/dp_display.c | 13 ++++++-------
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 5ddb4e8..8b71013 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1545,7 +1545,7 @@ static int dp_ctrl_process_phy_test_request(struct dp_ctrl_private *ctrl)
 
 	ret = dp_ctrl_on_link(&ctrl->dp_ctrl);
 	if (!ret)
-		ret = dp_ctrl_on_stream(&ctrl->dp_ctrl);
+		ret = dp_ctrl_on_stream(&ctrl->dp_ctrl, false);
 	else
 		DRM_ERROR("failed to enable DP link controller\n");
 
@@ -1802,7 +1802,7 @@ static int dp_ctrl_link_retrain(struct dp_ctrl_private *ctrl)
 	return dp_ctrl_setup_main_link(ctrl, &training_step);
 }
 
-int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
+int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train)
 {
 	int ret = 0;
 	bool mainlink_ready = false;
@@ -1827,7 +1827,7 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
 		}
 	}
 
-	if (!dp_ctrl_channel_eq_ok(ctrl))
+	if (force_link_train || !dp_ctrl_channel_eq_ok(ctrl))
 		dp_ctrl_link_retrain(ctrl);
 
 	/* stop txing train pattern to end link training */
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
index 2433edb..dcc7af21 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
@@ -20,7 +20,7 @@ struct dp_ctrl {
 };
 
 int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl);
-int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl);
+int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train);
 int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl);
 int dp_ctrl_off(struct dp_ctrl *dp_ctrl);
 void dp_ctrl_push_idle(struct dp_ctrl *dp_ctrl);
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index bfc6581..9246421 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -892,7 +892,7 @@ static int dp_display_enable(struct dp_display_private *dp, u32 data)
 		return 0;
 	}
 
-	rc = dp_ctrl_on_stream(dp->ctrl);
+	rc = dp_ctrl_on_stream(dp->ctrl, data);
 	if (!rc)
 		dp_display->power_on = true;
 
@@ -1594,6 +1594,7 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 	int rc = 0;
 	struct dp_display_private *dp_display;
 	u32 state;
+	bool force_link_train = false;
 
 	dp_display = container_of(dp, struct dp_display_private, dp_display);
 	if (!dp_display->dp_mode.drm_mode.clock) {
@@ -1622,10 +1623,12 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 
 	state =  dp_display->hpd_state;
 
-	if (state == ST_DISPLAY_OFF)
+	if (state == ST_DISPLAY_OFF) {
 		dp_display_host_phy_init(dp_display);
+		force_link_train = 1;
+	}
 
-	dp_display_enable(dp_display, 0);
+	dp_display_enable(dp_display, force_link_train);
 
 	rc = dp_display_post_enable(dp);
 	if (rc) {
@@ -1634,10 +1637,6 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 		dp_display_unprepare(dp);
 	}
 
-	/* manual kick off plug event to train link */
-	if (state == ST_DISPLAY_OFF)
-		dp_add_event(dp_display, EV_IRQ_HPD_INT, 0, 0);
-
 	/* completed connection */
 	dp_display->hpd_state = ST_CONNECTED;
 
-- 
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