Quoting Kuogee Hsieh (2022-04-14 10:25:37)
> 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()
>
> Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
> Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> Reported-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/dp/dp_display.c | 42 ++++++++++++++++++++++++++++---------
> 1 file changed, 32 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..0b9a96f 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -230,6 +231,29 @@ void dp_display_signal_audio_complete(struct msm_dp *dp_display)
> complete_all(&dp->audio_comp);
> }
>
> +static int hpd_event_thread(void *data);
> +
> +static int dp_hpd_event_thread_start(struct dp_display_private *dp_priv)
> +{
> + int err = 0;
Drop local.
> +
> + 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");
> + err = PTR_ERR(dp_priv->ev_tsk);
return PTR_ERR(dp_priv->ev_tsk);
> + }
Newline
> + return err;
return 0;
> +}
> +
> +static void dp_hpd_event_thread_stop(struct dp_display_private *dp_priv)
> +{
> + 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 +293,7 @@ static int dp_display_bind(struct device *dev, struct device *master,
> if (rc)
> DRM_ERROR("Audio registration Dp failed\n");
>
> + rc = dp_hpd_event_thread_start(dp);
Forward declare this new function?
> end:
> return rc;
> }
> @@ -280,6 +305,9 @@ 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);
> + dp_hpd_event_thread_stop(dp);
> dp_power_client_deinit(dp->power);
> dp_aux_unregister(dp->aux);
> priv->dp[dp->id] = NULL;
> @@ -1054,7 +1082,7 @@ 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),
> @@ -1132,13 +1160,6 @@ static int hpd_event_thread(void *data)
> return 0;
> }
>
> -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");
> -}
And then dp_hpd_event_thread_start() be defined here? The bind/unbind
functions should be moved to the bottom of this file because they're
probe/remove basically. Please do that in a followup patch.
>
> static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
> {
