Messages in this thread | | | Date | Thu, 14 Apr 2022 10:15:51 -0700 | Subject | Re: [PATCH v2] drm/msm/dp: stop event kernel thread when DP unbind | From | Kuogee Hsieh <> |
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On 4/13/2022 4:19 PM, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2022-04-13 14:04:25) >> Current DP driver implementation, event thread is kept running >> after DP display is unbind. This patch fix this problem by disabling >> DP irq and stop event thread to exit gracefully at dp_display_unbind(). >> >> Changes in v2: >> -- start event thread at dp_display_bind() >> >> Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets") >> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> >> Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> >> --- >> drivers/gpu/drm/msm/dp/dp_display.c | 40 +++++++++++++++++++++++++++---------- >> 1 file changed, 30 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c >> index 01453db..943e4f1 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_display.c >> +++ b/drivers/gpu/drm/msm/dp/dp_display.c >> @@ -113,6 +113,7 @@ struct dp_display_private { >> u32 hpd_state; >> u32 event_pndx; >> u32 event_gndx; >> + struct task_struct *ev_tsk; >> struct dp_event event_list[DP_EVENT_Q_MAX]; >> spinlock_t event_lock; >> >> @@ -230,6 +231,31 @@ void dp_display_signal_audio_complete(struct msm_dp *dp_display) >> complete_all(&dp->audio_comp); >> } >> >> +static int hpd_event_thread(void *data); > Is there a reason why this is needed vs. defining the kthread start > function after hpd_event_thread()? too many code need to be relocated. > >> + >> +static void dp_hpd_event_setup(struct dp_display_private *dp_priv) > Maybe dp_hpd_event_thread_start()? > >> +{ >> + init_waitqueue_head(&dp_priv->event_q); >> + spin_lock_init(&dp_priv->event_lock); >> + >> + dp_priv->ev_tsk = kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler"); >> + >> + if (IS_ERR(dp_priv->ev_tsk)) >> + DRM_ERROR("failed to create DP event thread\n"); > Can we return an error from this function? > >> +} >> + >> +static void dp_hpd_event_stop(struct dp_display_private *dp_priv) > Maybe dp_hpd_event_thread_stop()? > >> +{ >> + if (IS_ERR(dp_priv->ev_tsk)) >> + return; > If we handled the error then this check becomes impossible. > >> + >> + kthread_stop(dp_priv->ev_tsk); >> + >> + /* reset event q to empty */ >> + dp_priv->event_gndx = 0; >> + dp_priv->event_pndx = 0; >> +} >> + >> static int dp_display_bind(struct device *dev, struct device *master, >> void *data) >> { >> @@ -269,6 +295,7 @@ static int dp_display_bind(struct device *dev, struct device *master, >> if (rc) >> DRM_ERROR("Audio registration Dp failed\n"); >> >> + dp_hpd_event_setup(dp); /* start event thread */ > The comment is useless, please remove. > >> end: >> return rc; >> } >> @@ -280,6 +307,8 @@ static void dp_display_unbind(struct device *dev, struct device *master, >> struct drm_device *drm = dev_get_drvdata(master); >> struct msm_drm_private *priv = drm->dev_private; >> >> + disable_irq(dp->irq); > Is the disable_irq() necessary? It would be nicer to silence the > hardware and remove the disable_irq() so that we can reason about the > code assuming the irq is always enabled after it is requested. > >> + dp_hpd_event_stop(dp); /* stop event thread */ >> dp_power_client_deinit(dp->power); >> dp_aux_unregister(dp->aux); >> priv->dp[dp->id] = NULL;
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