On 5/2/2022 6:13 PM, Stephen Boyd wrote:
Quoting Kuogee Hsieh (2022-05-02 16:04:28)
Event thread supposed to exit from its while loop after kthread_stop().
However there may has possibility that event thread is pending in the
middle of wait_event due to condition checking never become true.
To make sure event thread exit its loop after kthread_stop(), this
patch OR kthread_should_stop() into wait_event's condition checking
so that event thread will exit its loop after kernal_stop().
Changes in v2:
-- correct spelling error at commit title
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Fixes: 570d3e5d28db ("drm/msm/dp: stop event kernel thread when DP unbind")
Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_display.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index c388323..5200a58 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1106,12 +1106,17 @@ static int hpd_event_thread(void *data)
while (!kthread_should_stop()) {
if (timeout_mode) {
wait_event_timeout(dp_priv->event_q,
- (dp_priv->event_pndx == dp_priv->event_gndx),
- EVENT_TIMEOUT);
+ ((dp_priv->event_pndx == dp_priv->event_gndx) ||
Why the parenthesis (before and after)?
+ kthread_should_stop()), EVENT_TIMEOUT);
} else {
wait_event_interruptible(dp_priv->event_q,
- (dp_priv->event_pndx != dp_priv->event_gndx));
+ ((dp_priv->event_pndx != dp_priv->event_gndx) ||
Why the parenthesis (before and after)?
+ kthread_should_stop()));
}
+
+ if(kthread_should_stop())
Missing space after if
+ break;
Is it possible to move the wait_event to the end of the loop and always
run the loop initially? That way we don't have to check for
kthread_should_stop() again.
no, since we have to make sure q is not empty so that we can proceed to
service events.
bu ti thin we can use while (1) instead of while
(!kthread_should_stop()) since we have add kthread_should_stop() into
wait_event condition checking.
