Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Elimar Riesebieter]

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forwarded 438118 alsa-devel@alsa-project.org

stop

Hi all,

can one please have a lokk at this? aplay -N isn't working for the
OP.

On Thu, 16 Aug 2007 the mental interface of
Anders Boström told:

> >>>>> "ER" == Elimar Riesebieter <riesebie@lxtec.de> writes:
> 
>  >> strace aplay -N :
>  >> 
>  >> ...
>  >> open("/usr/lib/alsa-lib/libasound_module_rate_speexrate.so", O_RDONLY) = -1 ENOENT (No such file or directory)
> 
>  ER> This file is provided by
>  ER> libasound2-plugins: /usr/lib/alsa-lib/libasound_module_rate_speexrate.so
> 
>  ER> Please install libasound2-plugins and try again.
> 
> Thanks for the suggestion.
> 
> Unfortunately, it didn't solve my problem, no sound when non-blocking
> mode is used. New strace:
> 
> strace aplay -N :
> ...
> open("/usr/lib/alsa-lib/libasound_module_rate_speexrate.so", O_RDONLY) = 5
> read(5, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\20\22\0"..., 832) = 832
> fstat(5, {st_mode=S_IFREG|0644, st_size=20848, ...}) = 0
> mmap(NULL, 2116136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 5, 0) = 0x2b9f792fe000
> mprotect(0x2b9f79302000, 2097152, PROT_NONE) = 0
> mmap(0x2b9f79502000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 5, 0x4000) = 0x2b9f79502000
> close(5)                                = 0
> ioctl(4, 0xc2604110, 0x7fff3269dec0)    = 0
> ioctl(4, 0xc2604110, 0x7fff3269dec0)    = 0
> ioctl(4, 0xc2604110, 0x7fff3269de00)    = 0
> ioctl(4, 0xc2604110, 0x7fff3269de00)    = 0
> ioctl(4, 0xc2604110, 0x7fff3269ddd0)    = 0
> ioctl(4, 0xc2604110, 0x7fff3269ddc0)    = 0
> ioctl(4, 0xc2604111, 0x7fff3269ddc0)    = 0
> ioctl(4, 0xc0884113, 0x7fff3269dd10)    = 0
> ioctl(4, 0x80184132, 0x7fff3269dc70)    = 0
> mmap(NULL, 49152, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0) = 0x2b9f79503000
> ioctl(4, 0xc0884113, 0x624e88)          = 0
> ioctl(4, 0x4140, 0)                     = 0
> ioctl(4, 0xc0884113, 0x624e88)          = 0
> read(3, "\377eO\333\337\370\344}\335_\377\330^l\356\361`j\336_l"..., 1001) = 1001
> read(3, "n{u^\342zl~e~_[\365_y\362_\363\350\337n[\347nmi`\367y\344"..., 604) = 604
> ioctl(4, 0x4144, 0x2b9f785d8000)        = -1 EAGAIN (Resource temporarily unavailable)
> close(3)                                = 0
> ioctl(4, 0x4143, 0x3)                   = 0
> munmap(0x2b9f79503000, 49152)           = 0
> ioctl(4, 0x4112, 0)                     = 0
> close(4)                                = 0
> munmap(0x2b9f785d7000, 4096)            = 0
> munmap(0x2b9f785d8000, 4096)            = 0
> munmap(0x2b9f792fe000, 2116136)         = 0
> exit_group(0)                           = ?

I have no idea, so forwarded to alsa-dev then.

THX in advance

Elimar


-- 
  Experience is something you don't get until 
  just after you need it!

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Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Takashi Iwai]

At Tue, 11 Sep 2007 18:08:11 +0200,
Elimar Riesebieter wrote:
> 
> forwarded 438118 alsa-devel@alsa-project.org
> 
> stop
> 
> Hi all,
> 
> can one please have a lokk at this? aplay -N isn't working for the
> OP.

Cannot reproduce here.  Could you _post_ more details?


thanks,

Takashi


> On Thu, 16 Aug 2007 the mental interface of
> Anders Boström told:
> 
> > >>>>> "ER" == Elimar Riesebieter <riesebie@lxtec.de> writes:
> > 
> >  >> strace aplay -N :
> >  >> 
> >  >> ...
> >  >> open("/usr/lib/alsa-lib/libasound_module_rate_speexrate.so", O_RDONLY) = -1 ENOENT (No such file or directory)
> > 
> >  ER> This file is provided by
> >  ER> libasound2-plugins: /usr/lib/alsa-lib/libasound_module_rate_speexrate.so
> > 
> >  ER> Please install libasound2-plugins and try again.
> > 
> > Thanks for the suggestion.
> > 
> > Unfortunately, it didn't solve my problem, no sound when non-blocking
> > mode is used. New strace:
> > 
> > strace aplay -N :
> > ...
> > open("/usr/lib/alsa-lib/libasound_module_rate_speexrate.so", O_RDONLY) = 5
> > read(5, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\20\22\0"..., 832) = 832
> > fstat(5, {st_mode=S_IFREG|0644, st_size=20848, ...}) = 0
> > mmap(NULL, 2116136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 5, 0) = 0x2b9f792fe000
> > mprotect(0x2b9f79302000, 2097152, PROT_NONE) = 0
> > mmap(0x2b9f79502000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 5, 0x4000) = 0x2b9f79502000
> > close(5)                                = 0
> > ioctl(4, 0xc2604110, 0x7fff3269dec0)    = 0
> > ioctl(4, 0xc2604110, 0x7fff3269dec0)    = 0
> > ioctl(4, 0xc2604110, 0x7fff3269de00)    = 0
> > ioctl(4, 0xc2604110, 0x7fff3269de00)    = 0
> > ioctl(4, 0xc2604110, 0x7fff3269ddd0)    = 0
> > ioctl(4, 0xc2604110, 0x7fff3269ddc0)    = 0
> > ioctl(4, 0xc2604111, 0x7fff3269ddc0)    = 0
> > ioctl(4, 0xc0884113, 0x7fff3269dd10)    = 0
> > ioctl(4, 0x80184132, 0x7fff3269dc70)    = 0
> > mmap(NULL, 49152, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0) = 0x2b9f79503000
> > ioctl(4, 0xc0884113, 0x624e88)          = 0
> > ioctl(4, 0x4140, 0)                     = 0
> > ioctl(4, 0xc0884113, 0x624e88)          = 0
> > read(3, "\377eO\333\337\370\344}\335_\377\330^l\356\361`j\336_l"..., 1001) = 1001
> > read(3, "n{u^\342zl~e~_[\365_y\362_\363\350\337n[\347nmi`\367y\344"..., 604) = 604
> > ioctl(4, 0x4144, 0x2b9f785d8000)        = -1 EAGAIN (Resource temporarily unavailable)
> > close(3)                                = 0
> > ioctl(4, 0x4143, 0x3)                   = 0
> > munmap(0x2b9f79503000, 49152)           = 0
> > ioctl(4, 0x4112, 0)                     = 0
> > close(4)                                = 0
> > munmap(0x2b9f785d7000, 4096)            = 0
> > munmap(0x2b9f785d8000, 4096)            = 0
> > munmap(0x2b9f792fe000, 2116136)         = 0
> > exit_group(0)                           = ?
> 
> I have no idea, so forwarded to alsa-dev then.
> 
> THX in advance
> 
> Elimar
> 
> 
> -- 
>   Experience is something you don't get until 
>   just after you need it!

Bug#438118: [alsa-devel] [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Anders Boström]

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>>>>> "TI" == Takashi Iwai <tiwai@suse.de> writes:

Hi!

 >> Hi all,
 >> 
 >> can one please have a lokk at this? aplay -N isn't working for the
 >> OP.

 TI> Cannot reproduce here.  Could you _post_ more details?

OK, I've tested more, and discovered that the problem seems to be that
the end of the sound is cut in non-blocking mode. And if I play a very
short sound-file, I can't hear anything. Blocking mode works fine.

When using non-blocking mode, an strace contains "ioctl(4, 0x4144,
0x2b9f785d8000)        = -1 EAGAIN (Resource temporarily
unavailable)". Blocking mode never contains the EAGAIN response.

I attach two files. When playing halt.au, I can only hear the start,
about as much as "ha". When playing metal.au, I can't hear anything.

System info:

ASUS A8V Deluxe motherboard with Athlon 64 3500+ CPU
VIA 8237 with ALC850 sound
Linux 2.6.22.2 kernel for amd64
Debian testing amd64 with:
alsa-utils 1.0.14-1
libasound2 1.0.14a-2
libc6 2.6.1-1

I hope this helps. Please ask if you need more info.

/ Anders

 >> On Thu, 16 Aug 2007 the mental interface of
 >> Anders Boström told:
 >> 
 >> > >>>>> "ER" == Elimar Riesebieter <riesebie@lxtec.de> writes:
 >> > 
 >> >  >> strace aplay -N :
 >> >  >> 
 >> >  >> ...
 >> >  >> open("/usr/lib/alsa-lib/libasound_module_rate_speexrate.so", O_RDONLY) = -1 ENOENT (No such file or directory)
 >> > 
 >> >  ER> This file is provided by
 >> >  ER> libasound2-plugins: /usr/lib/alsa-lib/libasound_module_rate_speexrate.so
 >> > 
 >> >  ER> Please install libasound2-plugins and try again.
 >> > 
 >> > Thanks for the suggestion.
 >> > 
 >> > Unfortunately, it didn't solve my problem, no sound when non-blocking
 >> > mode is used. New strace:
 >> > 
 >> > strace aplay -N :
 >> > ...
 >> > open("/usr/lib/alsa-lib/libasound_module_rate_speexrate.so", O_RDONLY) = 5
 >> > read(5, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\20\22\0"..., 832) = 832
 >> > fstat(5, {st_mode=S_IFREG|0644, st_size=20848, ...}) = 0
 >> > mmap(NULL, 2116136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 5, 0) = 0x2b9f792fe000
 >> > mprotect(0x2b9f79302000, 2097152, PROT_NONE) = 0
 >> > mmap(0x2b9f79502000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 5, 0x4000) = 0x2b9f79502000
 >> > close(5)                                = 0
 >> > ioctl(4, 0xc2604110, 0x7fff3269dec0)    = 0
 >> > ioctl(4, 0xc2604110, 0x7fff3269dec0)    = 0
 >> > ioctl(4, 0xc2604110, 0x7fff3269de00)    = 0
 >> > ioctl(4, 0xc2604110, 0x7fff3269de00)    = 0
 >> > ioctl(4, 0xc2604110, 0x7fff3269ddd0)    = 0
 >> > ioctl(4, 0xc2604110, 0x7fff3269ddc0)    = 0
 >> > ioctl(4, 0xc2604111, 0x7fff3269ddc0)    = 0
 >> > ioctl(4, 0xc0884113, 0x7fff3269dd10)    = 0
 >> > ioctl(4, 0x80184132, 0x7fff3269dc70)    = 0
 >> > mmap(NULL, 49152, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0) = 0x2b9f79503000
 >> > ioctl(4, 0xc0884113, 0x624e88)          = 0
 >> > ioctl(4, 0x4140, 0)                     = 0
 >> > ioctl(4, 0xc0884113, 0x624e88)          = 0
 >> > read(3, "\377eO\333\337\370\344}\335_\377\330^l\356\361`j\336_l"..., 1001) = 1001
 >> > read(3, "n{u^\342zl~e~_[\365_y\362_\363\350\337n[\347nmi`\367y\344"..., 604) = 604
 >> > ioctl(4, 0x4144, 0x2b9f785d8000)        = -1 EAGAIN (Resource temporarily unavailable)
 >> > close(3)                                = 0
 >> > ioctl(4, 0x4143, 0x3)                   = 0
 >> > munmap(0x2b9f79503000, 49152)           = 0
 >> > ioctl(4, 0x4112, 0)                     = 0
 >> > close(4)                                = 0
 >> > munmap(0x2b9f785d7000, 4096)            = 0
 >> > munmap(0x2b9f785d8000, 4096)            = 0
 >> > munmap(0x2b9f792fe000, 2116136)         = 0
 >> > exit_group(0)                           = ?
 >> 
 >> I have no idea, so forwarded to alsa-dev then.
 >> 
 >> THX in advance
 >> 
 >> Elimar
 >> 
 >> 
 >> -- 
 >> Experience is something you don't get until 
 >> just after you need it!

[-- Attachment #2: halt.au --]
[-- Type: Audio/Basic, Size: 4698 bytes --]

[-- Attachment #3: metal.au --]
[-- Type: Audio/Basic, Size: 1638 bytes --]

Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Takashi Iwai]

At Tue, 18 Sep 2007 09:41:48 +0200 (CEST),
Anders Boström wrote:
> 
> >>>>> "TI" == Takashi Iwai <tiwai@suse.de> writes:
> 
> Hi!
> 
>  >> Hi all,
>  >> 
>  >> can one please have a lokk at this? aplay -N isn't working for the
>  >> OP.
> 
>  TI> Cannot reproduce here.  Could you _post_ more details?
> 
> OK, I've tested more, and discovered that the problem seems to be that
> the end of the sound is cut in non-blocking mode. And if I play a very
> short sound-file, I can't hear anything. Blocking mode works fine.
> 
> When using non-blocking mode, an strace contains "ioctl(4, 0x4144,
> 0x2b9f785d8000)        = -1 EAGAIN (Resource temporarily
> unavailable)". Blocking mode never contains the EAGAIN response.
> 
> I attach two files. When playing halt.au, I can only hear the start,
> about as much as "ha". When playing metal.au, I can't hear anything.

OK, thanks, I see the problem now.

I don't remember whether it's a feature or a bug.  The drain ioctl
rejects the non-block mode.

Anyway, a simple patch is below.  Let me know if it works.


Takashi

diff -r 0028e39ead78 core/pcm_native.c
--- a/core/pcm_native.c	Tue Sep 18 00:52:38 2007 +0200
+++ b/core/pcm_native.c	Tue Sep 18 17:44:31 2007 +0200
@@ -1368,8 +1368,6 @@ static int snd_pcm_prepare(struct snd_pc
 
 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;
 }

Bug#438118: [alsa-devel] [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Anders Boström]

>>>>> "TI" == Takashi Iwai <tiwai@suse.de> writes:

 TI> At Tue, 18 Sep 2007 09:41:48 +0200 (CEST),
 TI> Anders Boström wrote:
 >> 
 >> >>>>> "TI" == Takashi Iwai <tiwai@suse.de> writes:
 >> 
 >> >> can one please have a lokk at this? aplay -N isn't working for the
 >> >> OP.
 >> 
 TI> Cannot reproduce here.  Could you _post_ more details?
 >> 
 >> OK, I've tested more, and discovered that the problem seems to be that
 >> the end of the sound is cut in non-blocking mode. And if I play a very
 >> short sound-file, I can't hear anything. Blocking mode works fine.
 >> 
 >> When using non-blocking mode, an strace contains "ioctl(4, 0x4144,
 >> 0x2b9f785d8000)        = -1 EAGAIN (Resource temporarily
 >> unavailable)". Blocking mode never contains the EAGAIN response.
 >> 
 >> I attach two files. When playing halt.au, I can only hear the start,
 >> about as much as "ha". When playing metal.au, I can't hear anything.

 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> Anyway, a simple patch is below.  Let me know if it works.

It works fine! Thanks!

/ Anders

 TI> diff -r 0028e39ead78 core/pcm_native.c
 TI> --- a/core/pcm_native.c	Tue Sep 18 00:52:38 2007 +0200
 TI> +++ b/core/pcm_native.c	Tue Sep 18 17:44:31 2007 +0200
 TI> @@ -1368,8 +1368,6 @@ static int snd_pcm_prepare(struct snd_pc
 
 TI>  static int snd_pcm_pre_drain_init(struct snd_pcm_substream *substream, int state)
 TI>  {
 TI> -	if (substream->f_flags & O_NONBLOCK)
 TI> -		return -EAGAIN;
 substream-> runtime->trigger_master = substream;
 TI>  	return 0;
 TI>  }

Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Takashi Iwai]

At Thu, 27 Sep 2007 14:16:29 +0200 (CEST),
Anders Boström wrote:
> 
> >>>>> "TI" == Takashi Iwai <tiwai@suse.de> writes:
> 
>  TI> At Tue, 18 Sep 2007 09:41:48 +0200 (CEST),
>  TI> Anders Boström wrote:
>  >> 
>  >> >>>>> "TI" == Takashi Iwai <tiwai@suse.de> writes:
>  >> 
>  >> >> can one please have a lokk at this? aplay -N isn't working for the
>  >> >> OP.
>  >> 
>  TI> Cannot reproduce here.  Could you _post_ more details?
>  >> 
>  >> OK, I've tested more, and discovered that the problem seems to be that
>  >> the end of the sound is cut in non-blocking mode. And if I play a very
>  >> short sound-file, I can't hear anything. Blocking mode works fine.
>  >> 
>  >> When using non-blocking mode, an strace contains "ioctl(4, 0x4144,
>  >> 0x2b9f785d8000)        = -1 EAGAIN (Resource temporarily
>  >> unavailable)". Blocking mode never contains the EAGAIN response.
>  >> 
>  >> I attach two files. When playing halt.au, I can only hear the start,
>  >> about as much as "ha". When playing metal.au, I can't hear anything.
> 
>  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?

Yes, that's my opinion, too.  This particular ioctl is to block the
operation, so it should be allowed as long as it's called.

But I vaguely remember that we discussed about it, and the current
form is the result of that.  Namely, we can call
snd_pcm_nonblock(FALSE) explicitly before calling snd_pcm_drain().

Though, I prefer fixing the behavior in the core side to allow the
blocking with this call...  Any reasonable objections in mind?


Takashi

Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Anders Boström]

>>>>> "TI" == Takashi Iwai <tiwai@suse.de> 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...

/ Anders

Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Jaroslav Kysela]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1577 bytes --]

On Fri, 14 Dec 2007, Anders Boström wrote:

> >>>>> "TI" == Takashi Iwai <tiwai@suse.de> 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 <perex@perex.cz>
Linux Kernel Sound Maintainer
ALSA Project

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Re: [Pkg-alsa-devel] Bug#438118: alsa-utils: aplay non-blocking mode isn't working

[Takashi Iwai]

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@suse.de> 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