On Fri, 13 Dec 2019 14:05:31 +0100,
Kai Vehmanen wrote:
>
> Hey,
>
> On Tue, 10 Dec 2019, Takashi Iwai wrote:
>
> > This patch attempts to improve the situation by introducing the
> > standard waitqueue in the RIRB waiter side instead of polling. The
>
> this patch was part of the testing as well, so looks good. One minor
> nit only:
>
> > @@ -216,6 +216,9 @@ void snd_hdac_bus_update_rirb(struct hdac_bus *bus)
> > else if (bus->rirb.cmds[addr]) {
> > bus->rirb.res[addr] = res;
> > bus->rirb.cmds[addr]--;
> > + if (!bus->rirb.cmds[addr] &&
> > + waitqueue_active(&bus->rirb_wq))
> > + wake_up(&bus->rirb_wq);
>
> Checkpath would like to have a comment here:
>
> WARNING: waitqueue_active without comment
> #77: FILE: sound/hda/hdac_controller.c:220:
> + waitqueue_active(&bus->rirb_wq))
Yeah, that was known to me, too. Actually it's misleading; what
actually matters is the memory barrier or other synchronization there,
and this should work as is because of the current code path.
(Besides, majority of existing waitqueue_active() have no comments at
all :)
And, now I found wa_has_sleeper() as a better replacement of
waitqueue_active() that explicitly cares about synchronization.
So I'll change with this in a later patch (after unification to
hda-core).
thanks,
Takashi
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