[Freedreno] [PATCH v7] drm/msm/dp: stop event kernel thread when DP unbind

[Kuogee Hsieh]

On 4/15/2022 3:48 PM, Dmitry Baryshkov wrote:
> On Sat, 16 Apr 2022 at 01:34, Kuogee Hsieh <quic_khsieh at quicinc.com> wrote:
>> 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()
>>
>> Changes in v3:
>> -- disable all HDP interrupts at unbind
>> -- replace dp_hpd_event_setup() with dp_hpd_event_thread_start()
>> -- replace dp_hpd_event_stop() with dp_hpd_event_thread_stop()
>> -- move init_waitqueue_head(&dp->event_q) to probe()
>> -- move spin_lock_init(&dp->event_lock) to probe()
>>
>> Changes in v4:
>> -- relocate both dp_display_bind() and dp_display_unbind() to bottom of file
>>
>> Changes in v5:
>> -- cancel relocation of both dp_display_bind() and dp_display_unbind()
>>
>> Changes in v6:
>> -- move empty event q to dp_event_thread_start()
>>
>> Changes in v7:
>> -- call ktheread_stop() directly instead of dp_hpd_event_thread_stop() function
>>
>> Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
>> Signed-off-by: Kuogee Hsieh <quic_khsieh at quicinc.com>
>> Reported-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>> Reviewed-by: Stephen Boyd <swboyd at chromium.org>
>> ---
>>   drivers/gpu/drm/msm/dp/dp_display.c | 31 ++++++++++++++++++++++++-------
>>   1 file changed, 24 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>> index 01453db..680e500 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 +231,8 @@ void dp_display_signal_audio_complete(struct msm_dp *dp_display)
>>          complete_all(&dp->audio_comp);
>>   }
>>
>> +static int dp_hpd_event_thread_start(struct dp_display_private *dp_priv);
>> +
>>   static int dp_display_bind(struct device *dev, struct device *master,
>>                             void *data)
>>   {
>> @@ -269,6 +272,7 @@ static int dp_display_bind(struct device *dev, struct device *master,
>>          if (rc)
>>                  DRM_ERROR("Audio registration Dp failed\n");
> I think I asked it in v3 and didn't get an answer:
> Isn't 'goto end' missing here?
I did follow you suggestion at v3 and made changes at 
dp_hpd_event_thread_start()
>> +       rc = dp_hpd_event_thread_start(dp);
> if (rc) { DRM_ERROR(....); goto end; }
> return 0;
>
> Please.
This is at dp_display_bind(),  "end" is the next statement why goto needed?
>>   end:
>>          return rc;
>>   }
>> @@ -280,6 +284,11 @@ 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 all HPD interrupts */
>> +       dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, false);
>> +
>> +       kthread_stop(dp->ev_tsk);
>> +
>>          dp_power_client_deinit(dp->power);
>>          dp_aux_unregister(dp->aux);
>>          priv->dp[dp->id] = NULL;
>> @@ -1054,7 +1063,7 @@ static int hpd_event_thread(void *data)
>>
>>          dp_priv = (struct dp_display_private *)data;
>>
>> -       while (1) {
>> +       while (!kthread_should_stop()) {
>>                  if (timeout_mode) {
>>                          wait_event_timeout(dp_priv->event_q,
>>                                  (dp_priv->event_pndx == dp_priv->event_gndx),
>> @@ -1132,12 +1141,19 @@ static int hpd_event_thread(void *data)
>>          return 0;
>>   }
>>
>> -static void dp_hpd_event_setup(struct dp_display_private *dp_priv)
>> +static int dp_hpd_event_thread_start(struct dp_display_private *dp_priv)
>>   {
>> -       init_waitqueue_head(&dp_priv->event_q);
>> -       spin_lock_init(&dp_priv->event_lock);
>> +       /* set event q to empty */
>> +       dp_priv->event_gndx = 0;
>> +       dp_priv->event_pndx = 0;
>> +
>> +       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");
>> +               return PTR_ERR(dp_priv->ev_tsk);
>> +       }
>>
>> -       kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler");
>> +       return 0;
>>   }
>>
>>   static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
>> @@ -1266,7 +1282,10 @@ static int dp_display_probe(struct platform_device *pdev)
>>                  return -EPROBE_DEFER;
>>          }
>>
>> +       /* setup event q */
>>          mutex_init(&dp->event_mutex);
>> +       init_waitqueue_head(&dp->event_q);
>> +       spin_lock_init(&dp->event_lock);
>>
>>          /* Store DP audio handle inside DP display */
>>          dp->dp_display.dp_audio = dp->audio;
>> @@ -1441,8 +1460,6 @@ void msm_dp_irq_postinstall(struct msm_dp *dp_display)
>>
>>          dp = container_of(dp_display, struct dp_display_private, dp_display);
>>
>> -       dp_hpd_event_setup(dp);
>> -
>>          dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 100);
>>   }
>>
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project
>>
>