On 6/14/2022 2:59 PM, Stephen Boyd wrote:
Quoting Kuogee Hsieh (2022-06-14 14:05:02)
Display resolution change is implemented through drm modeset. Older
modeset (resolution) has to be disabled first before newer modeset
(resolution) can be enabled. Display disable will turn off both
pixel clock and main link clock so that main link have to be
re-trained during display enable to have new video stream flow
again. At current implementation, display enable function manually
kicks up irq_hpd_handle which will read panel link status and start
link training if link status is not in sync state.
However, there is rare case that a particular panel links status keep
staying in sync for some period of time after main link had been shut
down previously at display disabled. In this case, main link retraining
will not be executed by irq_hdp_handle(). Hence video stream of newer
display resolution will fail to be transmitted to panel due to main
link is not in sync between host and panel.
This patch will bypass irq_hpd_hanle() in favor of directly call
s/hanle/handle/
dp_ctrl_on_stream() to always perform link training in regardless of
main link status. So that no unexpected exception resolution change
failure cases will happen. Also this implementation are more efficient
than manual kicking off irq_hpd_handle function.
Changes in v2:
-- set force_link_train flag on DP only (is_edp == false)
Changes in v3:
-- revise commit text
-- add Fixes tag
Changes in v4:
-- revise commit text
Changes in v5:
-- fix spelling at commit text
Changes in v6:
-- split dp_ctrl_on_stream() for phy test case
-- revise commit text for modeset
Fixes: 62671d2ef24b ("drm/msm/dp: fixes wrong connection state caused by failure of link train")
Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_ctrl.c | 31 +++++++++++++++++++++++--------
drivers/gpu/drm/msm/dp/dp_ctrl.h | 3 ++-
drivers/gpu/drm/msm/dp/dp_display.c | 13 ++++++-------
3 files changed, 31 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index af7a80c..cb9c7af 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1807,7 +1807,27 @@ 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_phy_test_report(struct dp_ctrl *dp_ctrl)
+{
+ int ret = 0;
Drop assignment please.
+ struct dp_ctrl_private *ctrl;
+
+ ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
+
+ ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock;
+
+ ret = dp_ctrl_enable_stream_clocks(ctrl);
+ if (ret) {
+ DRM_ERROR("Failed to start pixel clocks. ret=%d\n", ret);
+ return ret;
+ }
+
+ dp_ctrl_send_phy_test_pattern(ctrl);
None of this code needs to be run in the normal display on case?
+
+ return 0;
+}
+
+int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train)
{
int ret = 0;
bool mainlink_ready = false;
@@ -1843,12 +1863,7 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
goto end;
}
- if (ctrl->link->sink_request & DP_TEST_LINK_PHY_TEST_PATTERN) {
- dp_ctrl_send_phy_test_pattern(ctrl);
- return 0;
- }
-
- 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_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index c388323..b6d25ab 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1688,10 +1689,12 @@ void dp_bridge_enable(struct drm_bridge *drm_bridge)
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 = true;
+ }
- dp_display_enable(dp_display, 0);
+ dp_display_enable(dp_display, force_link_train);
Do we need to pass it from here? Why can't dp_display_enable() simply
check for 'state == ST_DISPLAY_OFF' and then force retrain the link?
can we keep this as it is?
it is more readable that we do need force link re-training due to
ST_DISPLAY_OFF at top level.
Also we only need to do (state == ST_DISPLAY_OFF) checking one time.
