On 12/04/2022 03:21, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2022-04-11 17:08:49)
>> 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().
>>
>> Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
>> Signed-off-by: Kuogee Hsieh <[email protected]>
>
> Should add a Reported-by tag from Dmitry here.
>
>> ---
>> drivers/gpu/drm/msm/dp/dp_display.c | 24 ++++++++++++++++++++++--
>> 1 file changed, 22 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>> index 01453db..fa1ef8e 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -273,6 +274,8 @@ static int dp_display_bind(struct device *dev, struct device *master,
>> return rc;
>> }
>>
>> +static void dp_hpd_event_stop(struct dp_display_private *dp_priv);
>
> Why can't the function be defined here?
>
>> +
>> static void dp_display_unbind(struct device *dev, struct device *master,
>> void *data)
>> {
>> @@ -280,6 +283,8 @@ 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);
>> + dp_hpd_event_stop(dp);
>> dp_power_client_deinit(dp->power);
>> dp_aux_unregister(dp->aux);
>> priv->dp[dp->id] = NULL;
>> @@ -1054,7 +1059,7 @@ 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),
>> @@ -1137,7 +1142,22 @@ static void dp_hpd_event_setup(struct dp_display_private *dp_priv)
>> init_waitqueue_head(&dp_priv->event_q);
>> spin_lock_init(&dp_priv->event_lock);
>>
>> - kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler");
>> + 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");
>
> Why can't we error out? Why can't this kthread be started in probe?
Just my 2c. I don't think starting it in probe is a good idea. The
driver uses components, so, in my opinion, the thread should be started
from bind and stopped in unbind.
>
>> +}
>> +
>> +static void dp_hpd_event_stop(struct dp_display_private *dp_priv)
>> +{
>> + if (IS_ERR(dp_priv->ev_tsk))
>> + return;
>> +
>> + kthread_stop(dp_priv->ev_tsk);
>> +
>> + /* reset event q to empty */
>> + dp_priv->event_gndx = 0;
>> + dp_priv->event_pndx = 0;
>> }
>>
--
With best wishes
Dmitry
On 4/11/2022 5:22 PM, Dmitry Baryshkov wrote:
> On 12/04/2022 03:21, Stephen Boyd wrote:
>> Quoting Kuogee Hsieh (2022-04-11 17:08:49)
>>> 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().
>>>
>>> Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on
>>> Snapdragon Chipsets")
>>> Signed-off-by: Kuogee Hsieh <[email protected]>
>>
>> Should add a Reported-by tag from Dmitry here.
>>
>>> ---
>>> drivers/gpu/drm/msm/dp/dp_display.c | 24 ++++++++++++++++++++++--
>>> 1 file changed, 22 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
>>> b/drivers/gpu/drm/msm/dp/dp_display.c
>>> index 01453db..fa1ef8e 100644
>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>> @@ -273,6 +274,8 @@ static int dp_display_bind(struct device *dev,
>>> struct device *master,
>>> return rc;
>>> }
>>>
>>> +static void dp_hpd_event_stop(struct dp_display_private *dp_priv);
>>
>> Why can't the function be defined here?
>>
>>> +
>>> static void dp_display_unbind(struct device *dev, struct device
>>> *master,
>>> void *data)
>>> {
>>> @@ -280,6 +283,8 @@ 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);
>>> + dp_hpd_event_stop(dp);
>>> dp_power_client_deinit(dp->power);
>>> dp_aux_unregister(dp->aux);
>>> priv->dp[dp->id] = NULL;
>>> @@ -1054,7 +1059,7 @@ 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),
>>> @@ -1137,7 +1142,22 @@ static void dp_hpd_event_setup(struct
>>> dp_display_private *dp_priv)
>>> init_waitqueue_head(&dp_priv->event_q);
>>> spin_lock_init(&dp_priv->event_lock);
>>>
>>> - kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler");
>>> + 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");
>>
>> Why can't we error out? Why can't this kthread be started in probe?
>
> Just my 2c. I don't think starting it in probe is a good idea. The
> driver uses components, so, in my opinion, the thread should be started
> from bind and stopped in unbind.
Yes, I also agree it should be started in bind and stopped in unbind.
>
>>
>>> +}
>>> +
>>> +static void dp_hpd_event_stop(struct dp_display_private *dp_priv)
>>> +{
>>> + if (IS_ERR(dp_priv->ev_tsk))
>>> + return;
>>> +
>>> + kthread_stop(dp_priv->ev_tsk);
>>> +
>>> + /* reset event q to empty */
>>> + dp_priv->event_gndx = 0;
>>> + dp_priv->event_pndx = 0;
>>> }
>>>
>
>
Quoting Abhinav Kumar (2022-04-11 17:29:17)
>
>
> On 4/11/2022 5:22 PM, Dmitry Baryshkov wrote:
> > On 12/04/2022 03:21, Stephen Boyd wrote:
> >> Quoting Kuogee Hsieh (2022-04-11 17:08:49)
> >>> - kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler");
> >>> + 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");
> >>
> >> Why can't we error out? Why can't this kthread be started in probe?
> >
> > Just my 2c. I don't think starting it in probe is a good idea. The
> > driver uses components, so, in my opinion, the thread should be started
> > from bind and stopped in unbind.
>
> Yes, I also agree it should be started in bind and stopped in unbind.
>
Sounds good to me! I forgot that this is a component.