At Fri, 14 Dec 2007 11:53:11 +0100 (CET), Jaroslav Kysela wrote: > > On Fri, 14 Dec 2007, Anders Boström wrote: > > > >>>>> "TI" == Takashi Iwai <tiwai@xxxxxxx> 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. AFAIK, O_NONBLOCK doesn't define the behavior of each ioctl on POSIX at all. Some standard POSIX-defined ioctls block even with O_NONBLOCK indeed. > 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. Well, this can be kept as is, but it's a bit weird (and silly) behavior. Anyway, we'll need fix this bug in our own codes in alsa-utils first :) Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
