At Sat, 15 Aug 2009 23:40:36 -0400,Jon Smirl wrote:> > On Sat, Aug 15, 2009 at 11:53 AM, Jon Smirl<jonsmirl@xxxxxxxxx> wrote:> > void> > bfio_synch_stop(void)> > {> > int n;> >> > if (base_handle == NULL) {> > return;> > }> > FOR_IN_AND_OUT {> > for (n = 0; n < n_handles[IO]; n++) {> > I added:> snd_pcm_nonblock(handles[IO][n], 0)> snd_pcm_drain(handles[IO][n])> snd_pcm_nonblock(handles[IO][n], SND_PCM_NONBLOCK )> > > snd_pcm_close(handles[IO][n]);> > }> > }> > }> > This is not working correctly.> snd_pcm_nonblock(handles[IO][n], 0)> It does not remove O_NONBLOCK for some unknown reason.> > I added printf() to snd_pcm_hw_nonblock()> The fcntl is not getting an error.> if (fcntl(fd, F_SETFL, flags) < 0) {> Flags being set are 2 (O_RDWR).> > But when I get over to snd_pcm_pre_drain_init(), I get the -EAGAIN error.> static int snd_pcm_pre_drain_init(struct snd_pcm_substream *substream,> int state)> {> printk("snd_pcm_pre_drain_init\n");> if (substream->f_flags & O_NONBLOCK)> return -EAGAIN;> printk("snd_pcm_pre_drain_init 1\n");> substream->runtime->trigger_master = substream;> return 0;> }> So I have to conclude that fcntl(fd, F_SETFL, flags) is not removing> the O_NONBLOCK flag.
Yeah, you found a long-standing bug :)
Honestly, I think the current designed behavior is just annoying.An ioctl may be blocked, thus there is no real merit to return -EAGAINwith DRAIN ioctl.
So, my preferred solution is simply to remove the O_NONBLOCK checkin the code path above.
Another solution would be a patch like below (totally untested)...
Comments?
thanks,
Takashi
---diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.cindex d89c816..5d6b9ad 100644--- a/sound/core/pcm_native.c+++ b/sound/core/pcm_native.c@@ -1343,8 +1343,6 @@ static int snd_pcm_prepare(struct snd_pcm_substream *substream, static int snd_pcm_pre_drain_init(struct snd_pcm_substream *substream, int state) {- if (substream->f_flags & O_NONBLOCK)- return -EAGAIN; substream->runtime->trigger_master = substream; return 0; }@@ -1404,7 +1402,8 @@ static int snd_pcm_drop(struct snd_pcm_substream *substream); * After this call, all streams are supposed to be either SETUP or DRAINING * (capture only) state. */-static int snd_pcm_drain(struct snd_pcm_substream *substream)+static int snd_pcm_drain(struct snd_pcm_substream *substream,+ struct file *file) { struct snd_card *card; struct snd_pcm_runtime *runtime;@@ -1412,6 +1411,14 @@ static int snd_pcm_drain(struct snd_pcm_substream *substream) int result = 0; int i, num_drecs; struct drain_rec *drec, drec_tmp, *d;+ int f_flags;++ if (file)+ f_flags = file->f_flags;+ else+ f_flags = substream->f_flags;+ if (f_flags & O_NONBLOCK)+ return -EAGAIN; card = substream->pcm->card; runtime = substream->runtime;@@ -2556,7 +2563,7 @@ static int snd_pcm_common_ioctl1(struct file *file, return snd_pcm_hw_params_old_user(substream, arg); #endif case SNDRV_PCM_IOCTL_DRAIN:- return snd_pcm_drain(substream);+ return snd_pcm_drain(substream, file); case SNDRV_PCM_IOCTL_DROP: return snd_pcm_drop(substream); case SNDRV_PCM_IOCTL_PAUSE:_______________________________________________Alsa-devel mailing listAlsa-devel@xxxxxxxxxxxxxxxxxxxx://mailman.alsa-project.org/mailman/listinfo/alsa-devel
