Re: [PATCH] staging: vchiq: Fix local event signalling

From: Stefan Wahren
Date: Fri Jan 11 2019 - 19:14:39 EST



> Phil Elwell <phil@xxxxxxxxxxxxxxx> hat am 11. Januar 2019 um 12:34 geschrieben:
>
>
> Prior to the recent event reworking (see Fixes), thread synchronisation
> was implemented using completions, the worker thread being woken with
> a call to complete(). The replacement uses waitqueues, which are more
> like condition variables in that the waiting thread is only woken if
> the condition is true.
>
> When the VPU signals the ARM, it first sets the event's fired flag to
> indicate which event is being signalled, but the places in the
> ARM-side code where the worker thread is being woken -
> remote_event_signal_local via request_poll - did not do so as it
> wasn't previously necessary, and since the armed flag was being
> cleared this lead to a deadlock.
>
> Fixes: 852b2876a8a8 ("staging: vchiq: rework remove_event handling")
> Signed-off-by: Phil Elwell <phil@xxxxxxxxxxxxxxx>

Tested-by: Stefan Wahren <stefan.wahren@xxxxxxxx>

Thanks