Bluetooth headset driver

Bluetooth headset driver

[Christian Ege]

[-- Attachment #1: Type: text/plain, Size: 948 bytes --]


Hi anyone working on something simalar to this?
   http://www.dcs.gla.ac.uk/~jp/snd-bt-sco/

The author of this driver won't continue his work because he switched to MAC OS
;-(

I think the way he tried to integrate this driver into alsa isn't the best way.

I am not that kind of Kernel guru but if there are some other people arround
here interested in that stuff it shouldn't be too much work to integrate this
driver in alsa.

Or isn't there any interest in bluetooth communication ;-)


cu
chege

------------------------------------------------------------------

Name:   Christian Ege
mailto: christian.ege@cybertux.org
Tel:    +49 (0)160 97 35 24 24
ICQ:    265026543

WWW:    http://www.cybertux.org

PGP Key fingerprint:
E436 3E5D CE47 7D0E DB63  F383 B41A 5FCF D4A1 D7A0
Informationen zu PGP: ( http://www.gnupg.de/ )
==================================================================


----- Ende der weitergeleiteten Nachricht -----


[-- Attachment #2: Digitale PGP-Unterschrift --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

Re: Bluetooth headset driver

[Robert Rozman]

Hi,

I'd love to have headset support under Alsa. And there will be more of these
devices every day ...

Regards,

Robert.

----- Original Message ----- 
From: "Christian Ege" <chege@cybertux.info>
To: <alsa-devel@lists.sourceforge.net>
Sent: Monday, April 26, 2004 7:39 PM
Subject: [Alsa-devel] Bluetooth headset driver




-------------------------------------------------------
This SF.net email is sponsored by: The Robotic Monkeys at ThinkGeek
For a limited time only, get FREE Ground shipping on all orders of $35
or more. Hurry up and shop folks, this offer expires April 30th!
http://www.thinkgeek.com/freeshipping/?cpg=12297

Re: Bluetooth headset driver

[James Courtier-Dutton]

Christian Ege wrote:
> Hi anyone working on something simalar to this?
>    http://www.dcs.gla.ac.uk/~jp/snd-bt-sco/
> 
> The author of this driver won't continue his work because he switched to MAC OS
> ;-(
> 
> I think the way he tried to integrate this driver into alsa isn't the best way.
> 
> I am not that kind of Kernel guru but if there are some other people arround
> here interested in that stuff it shouldn't be too much work to integrate this
> driver in alsa.
> 
> Or isn't there any interest in bluetooth communication ;-)
> 
> 
> cu
> chege
> 

I have been working on a bluetooth alsa driver, but it turns out to be a 
lot more complicated that one would at first think.
1) The bluetooth headset profile is a "profile" and therefore deemed to 
be a user space and not a kernel space program.
2) The current bluez bluetooth stack in the kernel does not provide any 
"playback" position feedback, so we would not be able to implement 
snd_pcm_delay() and therefore it would be extremely difficult to make a 
low latency app using it. The first use of a headset profile is for full 
duplex speach, which requires low latency, so that is a problem.
3) audio data path would therefore go from alsa-lib(userspace) -> 
alsa-driver(kernel-space) -> headset profile (userspace) -> bluez stack 
(kernel space). Extremely messy in my view!
(What http://www.dcs.gla.ac.uk/~jp/snd-bt-sco/ currently does in fact)

Summary: -
Until the bluez stack provides a mechanism for us to do 
"snd_pcm_delay()", there is very little point advancing with the alsa 
side for bluetooth.

Who will want to use a headset that has large uncontrollable latencies?

Cheers
James



-------------------------------------------------------
This SF.net email is sponsored by: The Robotic Monkeys at ThinkGeek
For a limited time only, get FREE Ground shipping on all orders of $35
or more. Hurry up and shop folks, this offer expires April 30th!
http://www.thinkgeek.com/freeshipping/?cpg=12297