Messages in this thread | | | Date | Wed, 10 Aug 2022 16:57:51 -0700 | Subject | Re: [PATCH v3] drm/msm/dp: check hpd_state before push idle pattern at dp_bridge_disable() | From | Kuogee Hsieh <> |
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On 8/10/2022 3:22 PM, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2022-08-10 12:25:51) >> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c >> index b36f8b6..678289a 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_display.c >> +++ b/drivers/gpu/drm/msm/dp/dp_display.c >> @@ -1729,10 +1729,20 @@ void dp_bridge_disable(struct drm_bridge *drm_bridge) >> struct msm_dp_bridge *dp_bridge = to_dp_bridge(drm_bridge); >> struct msm_dp *dp = dp_bridge->dp_display; >> struct dp_display_private *dp_display; >> + u32 state; >> >> dp_display = container_of(dp, struct dp_display_private, dp_display); >> >> + mutex_lock(&dp_display->event_mutex); >> + >> + state = dp_display->hpd_state; >> + if (state != ST_DISCONNECT_PENDING && state != ST_CONNECTED) { > It's concerning that we have to check this at all. Are we still > interjecting into the disable path when the cable is disconnected?
yes,
The problem is not from cable disconnected.
There is a corner case that this function is called at drm shutdown (drm_release).
At that time, mainlink is not enabled, hence dp_ctrl_push_idle() will cause system crash.
>> + mutex_unlock(&dp_display->event_mutex); >> + return; >> + } >> + >> dp_ctrl_push_idle(dp_display->ctrl); >> + mutex_unlock(&dp_display->event_mutex);
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