Fw: [Bug 76413] arts does not follow ALSA API

Fw: [Bug 76413] arts does not follow ALSA API

[Florian Schmidt]

Might be of interest..

Begin forwarded message:

Date: 3 Mar 2004 12:13:15 -0000
From: Allan Sandfeld <kde@carewolf.com>
To: mista.tapas@gmx.net
Subject: [Bug 76413] arts does not follow ALSA API 


------- You are receiving this mail because: -------
You are a voter for the bug, or are watching someone who is.
      
http://bugs.kde.org/show_bug.cgi?id=76413      




------- Additional Comments From kde carewolf com  2004-03-03 13:13
-------
We would be happy to accept your patches. I've started to work on this
bug, but I know neither ALSA nor much of aRts.

Currently the ALSA-plugin in aRts only calls snd_pcm_poll_descriptors,
and uses the first returned fd there for later use in select. If I
understand you correctly we need to be able to handle multiple
file-descriptors, and can't be garantied that they have the right
direction?

Now how do we tell which of the returned descriptors are writefds and
which are readfds? The only solution I can think of right now is to
checks the revents and hope all the writable ones are already in a
POLLOUT state.

I am also worried about the ALSA-documentation which states the fds
returned by snd_pcm_poll_descriotors might be bogus.



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Fw: [Bug 76413] arts does not follow ALSA API

[Florian Schmidt]

might be of interest to you guys... 

Begin forwarded message:

Date: 19 Mar 2004 13:50:08 -0000
From: Allan Sandfeld <kde@carewolf.com>
To: mista.tapas@gmx.net
Subject: [Bug 76413] arts does not follow ALSA API 


------- You are receiving this mail because: -------
You are a voter for the bug, or are watching someone who is.
      
http://bugs.kde.org/show_bug.cgi?id=76413      
kde carewolf com changed:

           What    |Removed                     |Added
-----------------------------------------------------------------------
-----
             Status|NEW                         |UNCONFIRMED



------- Additional Comments From kde carewolf com  2004-03-19 14:50
-------
Okay, having researched the problem. The reason that dmix doesnt work
with aRts has nothing to do with how we use the alsa API because all our
assumptions are still true. snd_pcm_poll_descriptors() returns exactly
one descriptor, but calling select upon this descriptor no matter how it
is done will _never_ return. In other words the reason it doesnt work is
that dmix is broken!

I've looked a bit at how other projects use ALSA, and it seems we could
make it work if we used another API and disregarded the broken
descriptors alltogether, in other words if we rewrite the entire
audio-subsystem of aRts to work-around a bug in ALSA (I have no
intention of doing so).

Btw. I did make playback over dmix work, but the it required using
timing events rather than IO-events and thus CPU-usage was unacceptable.



-- 
kT



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Fw: [Bug 76413] arts does not follow ALSA API

[Florian Schmidt]

He sounds pissed..  :) If you get pissed by these forwards, please tell
me.. I figured they might be of interest..

Begin forwarded message:

Date: 19 Mar 2004 15:05:31 -0000
From: Allan Sandfeld <kde@carewolf.com>
To: mista.tapas@gmx.net
Subject: [Bug 76413] arts does not follow ALSA API 


------- You are receiving this mail because: -------
You are a voter for the bug, or are watching someone who is.
      
http://bugs.kde.org/show_bug.cgi?id=76413      




------- Additional Comments From kde carewolf com  2004-03-19 16:05
-------
CVS commit by carewolf: 

After venting my fury I calmed down and looked at the dmix-code. It
seems 
it is really more borken than broken, and nothing we can't work around.

- Make aRts work with dmix. Two important changes:
  1. Dmix uses read-events to signify write-events, so we need to
autodetect 
     what kind of crack ALSA is smoking today.
  2. Dmix needs to be started like a recorder even if this is contrary
     to the ALSA API documentation.

If everything works like expected I will backport and close bugs 76413
and 70802.

CCMAIL: 76413 bugs kde org
CCMAIL: 70802 bugs kde org


  M +110 -48   audioioalsa9.cc   1.6



-- 
kT



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Re: Fw: [Bug 76413] arts does not follow ALSA API

[James Courtier-Dutton]

Florian Schmidt wrote:
> He sounds pissed..  :) If you get pissed by these forwards, please tell
> me.. I figured they might be of interest..
> 
> Begin forwarded message:
> 
> Date: 19 Mar 2004 15:05:31 -0000
> From: Allan Sandfeld <kde@carewolf.com>
> To: mista.tapas@gmx.net
> Subject: [Bug 76413] arts does not follow ALSA API 
> 
> 
> ------- You are receiving this mail because: -------
> You are a voter for the bug, or are watching someone who is.
>       
> http://bugs.kde.org/show_bug.cgi?id=76413      
> 
> 
> 
> 
> ------- Additional Comments From kde carewolf com  2004-03-19 16:05
> -------
> CVS commit by carewolf: 
> 
> After venting my fury I calmed down and looked at the dmix-code. It
> seems 
> it is really more borken than broken, and nothing we can't work around.
> 
> - Make aRts work with dmix. Two important changes:
>   1. Dmix uses read-events to signify write-events, so we need to
> autodetect 
>      what kind of crack ALSA is smoking today.
>   2. Dmix needs to be started like a recorder even if this is contrary
>      to the ALSA API documentation.
> 
> If everything works like expected I will backport and close bugs 76413
> and 70802.
> 
> CCMAIL: 76413 bugs kde org
> CCMAIL: 70802 bugs kde org
> 
> 
>   M +110 -48   audioioalsa9.cc   1.6
> 
> 
> 
If there is a bug in alsa, we will fix it.
Can you post a small program to demonstrate the problem.

Cheers
James



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Re: Fw: [Bug 76413] arts does not follow ALSA API

[Jaroslav Kysela]

On Fri, 19 Mar 2004, James Courtier-Dutton wrote:

> > ------- You are receiving this mail because: -------
> > You are a voter for the bug, or are watching someone who is.
> >       
> > http://bugs.kde.org/show_bug.cgi?id=76413      
> > 
> > CCMAIL: 76413 bugs kde org
> > CCMAIL: 70802 bugs kde org
> > 
> > 
> >   M +110 -48   audioioalsa9.cc   1.6
> > 
>
> If there is a bug in alsa, we will fix it.
> Can you post a small program to demonstrate the problem.

It's not a bug, but this guy definitely wants to simplify his work.
He uses file descriptors directly without 
snd_pcm_poll_descriptors_revents(). The dmix plugin (and dshare)
are first plugins which don't return POLLOUT for playback but POLLIN
(because timer events are used as the event source).

						Jaroslav

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


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Re: Fw: [Bug 76413] arts does not follow ALSA API

[James Courtier-Dutton]

Jaroslav Kysela wrote:
> On Fri, 19 Mar 2004, James Courtier-Dutton wrote:
> 
> 
>>>------- You are receiving this mail because: -------
>>>You are a voter for the bug, or are watching someone who is.
>>>      
>>>http://bugs.kde.org/show_bug.cgi?id=76413      
>>>
>>>CCMAIL: 76413 bugs kde org
>>>CCMAIL: 70802 bugs kde org
>>>
>>>
>>>  M +110 -48   audioioalsa9.cc   1.6
>>>
>>
>>If there is a bug in alsa, we will fix it.
>>Can you post a small program to demonstrate the problem.
> 
> 
> It's not a bug, but this guy definitely wants to simplify his work.
> He uses file descriptors directly without 
> snd_pcm_poll_descriptors_revents(). The dmix plugin (and dshare)
> are first plugins which don't return POLLOUT for playback but POLLIN
> (because timer events are used as the event source).
> 
> 						Jaroslav
> 
> -----
> Jaroslav Kysela <perex@suse.cz>
> Linux Kernel Sound Maintainer
> ALSA Project, SuSE Labs
> 
> 

I read the thread:
 >>>http://bugs.kde.org/show_bug.cgi?id=76413

The guys there just don't understand what you told them. If they took 
the time to actually read what you said, they could easily fix their 
problem.

Summary: -
No bug in alsa.

Cheers
James




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Re: Fw: [Bug 76413] arts does not follow ALSA API

[Joerg Mayer]

On Fri, Mar 19, 2004 at 08:30:13PM +0000, James Courtier-Dutton wrote:
> The guys there just don't understand what you told them. If they took 
> the time to actually read what you said, they could easily fix their 
> problem.
> 
> Summary: -
> No bug in alsa.

Summary 2:
There seem to be quite a lot of projects that have problems to get native
alsa support right: wine, winex, arts, xmms...

How about a "alsa application developers meeting" once per month on IRC?
If that meeting would be announced on the developer mailing list of
projects that are known to use alsa, this might actually help.

The invitation should contain something along the line:
"If you have written code to use alsa, you should participate. Either because
you did it right and can help others to do so too or because you didn't and
in that case you should want to improve."

 Ciao
       Jörg
-- 
Joerg Mayer                                           <jmayer@loplof.de>
We are stuck with technology when what we really want is just stuff that
works. Some say that should read Microsoft instead of technology.


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Re: Fw: [Bug 76413] arts does not follow ALSA API

[James Courtier-Dutton]

Joerg Mayer wrote:
> On Fri, Mar 19, 2004 at 08:30:13PM +0000, James Courtier-Dutton wrote:
> 
>>The guys there just don't understand what you told them. If they took 
>>the time to actually read what you said, they could easily fix their 
>>problem.
>>
>>Summary: -
>>No bug in alsa.
> 
> 
> Summary 2:
> There seem to be quite a lot of projects that have problems to get native
> alsa support right: wine, winex, arts, xmms...
wine is only just starting to support alsa properly, due mainly to lack 
of real need to alsa support for a long time. They are starting to 
support it well now.
xmms don't support it well for obvious reasons. They charge people for 
OSS drivers, so the xmms alsa driver has to look worse!


> 
> How about a "alsa application developers meeting" once per month on IRC?
> If that meeting would be announced on the developer mailing list of
> projects that are known to use alsa, this might actually help.

Just reading the docs correctly should help.
I hang out on #alsa on freenode quite a lot, and will help if I have the 
time.

> 
> The invitation should contain something along the line:
> "If you have written code to use alsa, you should participate. Either because
> you did it right and can help others to do so too or because you didn't and
> in that case you should want to improve."
> 
>  Ciao
>        Jörg



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Re: Fw: [Bug 76413] arts does not follow ALSA API

[Måns Rullgård]

James Courtier-Dutton <James@superbug.demon.co.uk> writes:

> Joerg Mayer wrote:
>> On Fri, Mar 19, 2004 at 08:30:13PM +0000, James Courtier-Dutton wrote:
>>
>>> The guys there just don't understand what you told them. If they
>>> took the time to actually read what you said, they could easily fix
>>> their problem.
>>>
>>>Summary: -
>>>No bug in alsa.
>> Summary 2:
>> There seem to be quite a lot of projects that have problems to get native
>> alsa support right: wine, winex, arts, xmms...
> wine is only just starting to support alsa properly, due mainly to
> lack of real need to alsa support for a long time. They are starting
> to support it well now.
> xmms don't support it well for obvious reasons. They charge people for
> OSS drivers, so the xmms alsa driver has to look worse!

The funny thing is that they can't even get that right, unless, of
course, you consider random skips a sign of correctness.

-- 
Måns Rullgård
mru@kth.se



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