Re: hw_params()

Re: hw_params()

[Jaroslav Kysela]

On 26 Apr 2003, Giuliano Pochini wrote:

> hw_params() callback may be called multiple times. Is it guaranteed
> that before the second, third... call hw_free() is called ?

Nope. The hw_free call is optional. It's only explicitly called in 
close().

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs



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hw_params()

[Giuliano Pochini]

hw_params() callback may be called multiple times. Is it guaranteed
that before the second, third... call hw_free() is called ?


Bye.




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More than stereo (4 channels in my case)

[Tom Watson]

In a related project I used OSS (even paid for it) and got did a
program that played 4 channel sound files (of my own making).  On that
project I had a CMI sound chip (CMI 8738).  To get the thing to work
properly (the back two playback channels on the "line in" jack, I
needed to have a special mixer control set, and used ossmix to do the
job "ossmix misc.rear2lin on".

Fast forward to my current configuration:  VIA SouthBridge chip audio,
VT8233 (Vendor 1106, Device 3059, Rev 50, from /sbin/lspci).  I'd like
to do the same thing.  Now I've read quite a few of the examples and my
attempts to make some sense out of 'amixer' and 'aplay' are frustrating
me quite a bit.  I've got 0.9.2 alsa, and a couple of problems:
1)  The sound in the right channel has a lot of hash.  One time (god
knows what I did) it seemed to play OK.  I'm using 44.1 kHz sample
files (if that makes a difference), since the source code seems to want
48kHz (or so I surmise).
2)  The rear channels are nowhere to be found.  I suspect that I need
to turn on some switch in the mixer, but which one is becoming a
mystery to me.

Eventually I'll be moving to a different sound card (a Turtle Beach
Santa Cruz), then another one. I suspect that some of the same problems
might continue, so I'd like to solve them here first.  Any/all
suggestions would be welcome.

p.s.  While I will convert to alsa, will the OSS stuff work in
emulation??  Will I have similar controls available like the
misc.rear2lin mentioned above??  Is there any way I can put them into
the OSS emulation stuff??  I'd be willing to do so.

Thanks.

=====
-- 
Tom Watson
tsw@johana.com

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Re: More than stereo (4 channels in my case)

[James Courtier-Dutton]

Tom Watson wrote:

>In a related project I used OSS (even paid for it) and got did a
>program that played 4 channel sound files (of my own making).  On that
>project I had a CMI sound chip (CMI 8738).  To get the thing to work
>properly (the back two playback channels on the "line in" jack, I
>needed to have a special mixer control set, and used ossmix to do the
>job "ossmix misc.rear2lin on".
>
>Fast forward to my current configuration:  VIA SouthBridge chip audio,
>VT8233 (Vendor 1106, Device 3059, Rev 50, from /sbin/lspci).  I'd like
>to do the same thing.  Now I've read quite a few of the examples and my
>attempts to make some sense out of 'amixer' and 'aplay' are frustrating
>me quite a bit.  I've got 0.9.2 alsa, and a couple of problems:
>1)  The sound in the right channel has a lot of hash.  One time (god
>knows what I did) it seemed to play OK.  I'm using 44.1 kHz sample
>files (if that makes a difference), since the source code seems to want
>48kHz (or so I surmise).
>2)  The rear channels are nowhere to be found.  I suspect that I need
>to turn on some switch in the mixer, but which one is becoming a
>mystery to me.
>
>Eventually I'll be moving to a different sound card (a Turtle Beach
>Santa Cruz), then another one. I suspect that some of the same problems
>might continue, so I'd like to solve them here first.  Any/all
>suggestions would be welcome.
>
>p.s.  While I will convert to alsa, will the OSS stuff work in
>emulation??  Will I have similar controls available like the
>misc.rear2lin mentioned above??  Is there any way I can put them into
>the OSS emulation stuff??  I'd be willing to do so.
>
>Thanks.
>
>=====
>  
>
Although I do not have your sound card, I have a SB Live, and in order 
to get sound coming out of different speakers, one just uses a different 
device name at snd_pcm_open.
E.g. "front" for front speaker stereo,
 "rear" for rear speaker stereo,
"surround40" for 4-channel surround. (front and rear together)
"surround51" for 5.1 Surround. (front, rear, center and SubWoofer)
"default" for the same sound copied to all speakers.

All these device "aliases" are already set up for the sb live. You might 
have to configure some alsa config files to get them to be the same for 
your sound card.
All the alsa config files I have are in /usr/share/alsa and 
/usr/share/alsa/pcm

Cheers
James




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Re: More than stereo (4 channels in my case)

[Takashi Iwai]

At Sun, 27 Apr 2003 01:02:49 -0700 (PDT),
Tom Watson wrote:
> 
> In a related project I used OSS (even paid for it) and got did a
> program that played 4 channel sound files (of my own making).  On that
> project I had a CMI sound chip (CMI 8738).  To get the thing to work
> properly (the back two playback channels on the "line in" jack, I
> needed to have a special mixer control set, and used ossmix to do the
> job "ossmix misc.rear2lin on".
 
you can toggle this via alsamixer on the fly.
check alsa-kernel/Documentation/CMIPCI.txt for details.

> Fast forward to my current configuration:  VIA SouthBridge chip audio,
> VT8233 (Vendor 1106, Device 3059, Rev 50, from /sbin/lspci).  I'd like
> to do the same thing.  Now I've read quite a few of the examples and my
> attempts to make some sense out of 'amixer' and 'aplay' are frustrating
> me quite a bit.  I've got 0.9.2 alsa, and a couple of problems:
> 1)  The sound in the right channel has a lot of hash.  One time (god
> knows what I did) it seemed to play OK.  I'm using 44.1 kHz sample
> files (if that makes a difference), since the source code seems to want
> 48kHz (or so I surmise).

it looks like a bug of AWARD BIOS.
i'll put a workaround soon to cvs.

> 2)  The rear channels are nowhere to be found.  I suspect that I need
> to turn on some switch in the mixer, but which one is becoming a
> mystery to me.

the multi-channel is supported on the second pcm device.  the first
pcm device is so-called "direct sound" pcm, and supports up to 4
playbacks at the same time but only for two channels.

for 4-channel output, there is no special configuration.
(you need to adjust "Surround" volumes, though.)
depending on the board, you might need to toggle some switches to
configure the line-in as rear output.

> Eventually I'll be moving to a different sound card (a Turtle Beach
> Santa Cruz), then another one. I suspect that some of the same problems
> might continue, so I'd like to solve them here first.  Any/all
> suggestions would be welcome.

is it cs46xx?  then it should work.  just raise the surround volume as
above.

> p.s.  While I will convert to alsa, will the OSS stuff work in
> emulation??  Will I have similar controls available like the
> misc.rear2lin mentioned above??  Is there any way I can put them into
> the OSS emulation stuff??  I'd be willing to do so.

so far, no.  using amixer (or alsamixer) wouldn't suffice?


Takashi


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Re: More than stereo (4 channels in my case)

[Tom Watson]

--- Takashi Iwai <tiwai@suse.de> wrote:
> At Sun, 27 Apr 2003 01:02:49 -0700 (PDT),
> Tom Watson wrote:
> > 
> > In a related project I used OSS (even paid for it) and got did a
> > program that played 4 channel sound files (of my own making).  On
> that
> > project I had a CMI sound chip (CMI 8738).  To get the thing to
> work
> > properly (the back two playback channels on the "line in" jack, I
> > needed to have a special mixer control set, and used ossmix to do
> the
> > job "ossmix misc.rear2lin on".
>  
> you can toggle this via alsamixer on the fly.
> check alsa-kernel/Documentation/CMIPCI.txt for details.

WOW!!  Documentation.  This is VERY helpful for getting the settings
right for the mixer controls.  In particular, it explains the "copy
front to rear" (oss: misc.4spk) and "rear output is line in jack"
(oss:misc.rear2lin).

> 
> > Fast forward to my current configuration:  VIA SouthBridge chip
> audio,
> > VT8233 (Vendor 1106, Device 3059, Rev 50, from /sbin/lspci).  I'd
> like
> > to do the same thing.  Now I've read quite a few of the examples
> and my
> > attempts to make some sense out of 'amixer' and 'aplay' are
> frustrating
> > me quite a bit.  I've got 0.9.2 alsa, and a couple of problems:
> > 1)  The sound in the right channel has a lot of hash.  One time
> (god
> > knows what I did) it seemed to play OK.  I'm using 44.1 kHz sample
> > files (if that makes a difference), since the source code seems to
> want
> > 48kHz (or so I surmise).
> 
> it looks like a bug of AWARD BIOS.
> i'll put a workaround soon to cvs.

Just curious, what was/is the problem??  Somehow I could get it to come
and go.

> 
> > 2)  The rear channels are nowhere to be found.  I suspect that I
> need
> > to turn on some switch in the mixer, but which one is becoming a
> > mystery to me.
> 
> the multi-channel is supported on the second pcm device.  the first
> pcm device is so-called "direct sound" pcm, and supports up to 4
> playbacks at the same time but only for two channels.
> 
> for 4-channel output, there is no special configuration.
> (you need to adjust "Surround" volumes, though.)
> depending on the board, you might need to toggle some switches to
> configure the line-in as rear output.

OK, this is nice, but I'd like to know how to shift them using the
'amixer' program.  Is there an equivalent set of documentation like the
CMI8738 documentation (CMPPCI.txt) that explains the mixer controls as
detailed.  Also, why aren't the mixer controls (these are both AC'97
audio goodies) similar for similar functions.  This would be a GREAT
bonus, as the command line stuff could go from platform to platform.

> 
> > Eventually I'll be moving to a different sound card (a Turtle Beach
> > Santa Cruz), then another one. I suspect that some of the same
> problems
> > might continue, so I'd like to solve them here first.  Any/all
> > suggestions would be welcome.
> 
> is it cs46xx?  then it should work.  just raise the surround volume
> as
> above.

Yup, it is a cs46xx chip, ought to be OK.  I have yet to try it though.
  That's next on the list.

> 
> > p.s.  While I will convert to alsa, will the OSS stuff work in
> > emulation??  Will I have similar controls available like the
> > misc.rear2lin mentioned above??  Is there any way I can put them
> into
> > the OSS emulation stuff??  I'd be willing to do so.
> 
> so far, no.  using amixer (or alsamixer) wouldn't suffice?

Yes, it would.  My "problem" (yes I need to read more!!) is that the
OSS mixer command line control goodie (ossmix) was pretty simple to
understand.  The program 'amixer' while it does more is a bit more
difficult to understand.

By the way...  Just how does the mapping from alsa controls to oss
controls happen?  Is this unique for each chip, or a general thing??

Maybe if we have some knowledge of each it would be easier to
understand.
> 
> 
> Takashi
> 


Thanks so much.  All of this is very informative.

=====
-- 
Tom Watson
tsw@johana.com

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