On Fri, 14 Dec 2007, Anders Boström wrote:
> >>>>> "TI" == Takashi Iwai <[EMAIL PROTECTED]> writes:
>
> TI> OK, thanks, I see the problem now.
> >>
> TI> I don't remember whether it's a feature or a bug. The drain ioctl
> TI> rejects the non-block mode.
> >>
> >> I can understand the idea here, that in non-blocking mode, no call
> >> should block, ever. But on the other hand, if you call the drain
> >> ioctl, you probably expect it to work, even in non-blocking mode. Why
> >> would you otherwise call it?
>
> TI> Yes, that's my opinion, too. This particular ioctl is to block the
> TI> operation, so it should be allowed as long as it's called.
>
> TI> But I vaguely remember that we discussed about it, and the current
> TI> form is the result of that. Namely, we can call
> TI> snd_pcm_nonblock(FALSE) explicitly before calling snd_pcm_drain().
>
> TI> Though, I prefer fixing the behavior in the core side to allow the
> TI> blocking with this call... Any reasonable objections in mind?
>
> Any progress in including a solotion to this bug in mainstream
> alsa & linux kernel? Has anything been done? The patch works fine for
> me...
I think that this proposal breaks basic posix rules. Application should
change blocking state itself. And non-blocking snd_pcm_drain() still makes
sense - it will return state of stream (-EAGAIN - unfinished) or reset PCM
state to SETUP in case when all data are played.
Jaroslav
-----
Jaroslav Kysela <[EMAIL PROTECTED]>
Linux Kernel Sound Maintainer
ALSA Project
