[9fans] AC'97 - Plan9

This is a discussion on [9fans] AC'97 - Plan9 ; I just wanted to give a heads up since I know Dave has students working on this and it seems silly to have duplicated work. Aki has a driver on 9grid.net that works for my chipset. I just grabbed: http://9grid.net/aki/src/9/pc/audio.h ...

+ Reply to Thread
Results 1 to 11 of 11

Thread: [9fans] AC'97

  1. [9fans] AC'97

    I just wanted to give a heads up since I know Dave has students working on this
    and it seems silly to have duplicated work. Aki has a driver on 9grid.net that
    works for my chipset. I just grabbed:

    http://9grid.net/aki/src/9/pc/audio.h
    http://9grid.net/aki/src/9/pc/audioac97.h
    http://9grid.net/aki/src/9/pc/audioac97mix.h
    http://9grid.net/aki/src/9/port/devaudio.c

    My card probes with:

    #A0: ac97 port 0x18c0 mixport 0x1c00 irq 10
    #A0: ac97 warm reset
    #A0: ac97 codecs ready: sdin0 sdin1
    #A0: ac97 codecs resumed:
    #A0: ac97 codec ext: vra spdif

    9top% madplay '02 - Birdhouse In Your Soul.mp3'
    MPEG Audio Decoder version 0.11.4 (beta) - Copyright (C) 2000 Robert Leslie
    Title: Birdhouse In Your Soul Artist: They Might Be Giants
    Album: Flood Genre: Other
    Year: 1990 Track: 2 Comment:
    ID3: version 2.3.0, flags 0x00, size 2171 bytes
    Album/Movie/Show title: Flood
    Title/Songname/Content description: Birdhouse In Your Soul
    Year: 1990
    ID3: unhandled MCDI (Music CD Identifier): flags 0x0000, 804 bytes
    Track number/Position in set: 2
    Content type: Alternative
    ID3: unhandled PRIV (Private frame): flags 0x0000, 14 bytes
    ID3: unhandled PRIV (Private frame): flags 0x0000, 17 bytes
    Lead performer(s)/Soloist(s): They Might Be Giants
    Length: 200333

    (I'm a geek, am I not obliged to like TMBG?)

    Now, this is fine and dandy, but I have questions.

    Aki, why isn't this on sources? Why didn't you post to 9fans saying that
    this existed? I suppose writing a driver is good learning material, but I have
    the feeling now that Dave's students are doing a good deal of duplicate
    work now.

    Is there some reason this can't be included into Plan 9? Was this ever
    suggested off-list?

    --dho


  2. Re: [9fans] Re: AC'97

    We've implemented the audio playback for AC97 for ICH controllers and the
    project description can be found here
    http://www.andrew.cmu.edu/user/bbhavsar/ac97.html

    We have tested the code thoroughly and in the final stages of code review
    with Prof. Dave Eckhardt.

    -Bankim.

    On 4/16/07, Devon H. O'Dell wrote:
    >
    > > http://9grid.net/aki/src/9/pc/audioac97.h
    > > http://9grid.net/aki/src/9/pc/audioac97mix.h

    >
    > Sorry, that should be
    > http://9grid.net/aki/src/9/pc/audioac97.c
    > http://9grid.net/aki/src/9/pc/audioac97mix.c
    >
    > --dho
    >



  3. Re: [9fans] Re: AC'97

    > We've implemented the audio playback for AC97 for ICH controllers and the
    > project description can be found here


    Excellent work, this will be widely useful, well done.

    -Steve

  4. Re: [9fans] Re: AC'97

    i second the motion.

    - erik

  5. Re: [9fans] Re: AC'97

    2007/4/16, Steve Simon :
    > > We've implemented the audio playback for AC97 for ICH controllers and the
    > > project description can be found here

    >
    > Excellent work, this will be widely useful, well done.
    >
    > -Steve


    I agree; I just wonder why this work was duplicated.

    --dho

  6. Re: [9fans] AC'97

    On 4/16/07, Devon H. O'Dell wrote:
    > I just wanted to give a heads up since I know Dave has students working on this
    > and it seems silly to have duplicated work.


    It is not silly, it is the Plan 9 way: duplicate as much work as
    possible, and if you do something, bury it somewhere where nobody
    could ever find it, god forbid someone could find it useful!

    If you poke around 9grid.net you will find also references to a
    working gcc port, and now I heard that there are different people
    working on ape and non-ape python ports.

    Honestly, aren't you happy about the amazing transparency and
    efficiency of this development model?

    uriel

  7. Re: [9fans] AC'97

    > It is not silly, it is the Plan 9 way:

    that's bs.


  8. Re: [9fans] AC'97

    let's just suppose there is already an ac97 driver that does everything
    available. the excercize of writing another driver is still useful. there's
    a lot to be learned through the process. i saw a lot of good information
    on the web page describing the process that wasn't present in the link
    to source on 9grid. i may need to write an ac97 driver for a non-plan9
    kernel. i think i could use some of the tips presented there.

    so, uriel, could you explain why these folk's education needs to benefit you
    or to fit into some grand development model?

    - erik


  9. Re: [9fans] AC'97

    2007/4/16, erik quanstrom :
    > let's just suppose there is already an ac97 driver that does everything
    > available. the excercize of writing another driver is still useful. there's
    > a lot to be learned through the process. i saw a lot of good information
    > on the web page describing the process that wasn't present in the link
    > to source on 9grid. i may need to write an ac97 driver for a non-plan9
    > kernel. i think i could use some of the tips presented there.


    Similar to what I've said before in this thread. In fact, that link
    did indeed provide a good bit of useful information. If only all
    drivers were written with this model in mind! Porting would be a lot
    easier. My original question was certainly not intended to downplay
    the efforts of either party.

    > so, uriel, could you explain why these folk's education needs to benefit you
    > or to fit into some grand development model?


    Wait, this is exactly what I wanted to avoid. Let's kill the flames,
    please. Or avoid them before they start.

    > - erik
    >
    >


  10. Re: [9fans] AC'97

    > Aki has a driver on 9grid.net that works for my chipset.

    That looks like very professional code. We've wanted AC '97
    support for a while, so any way we end up with it is good for
    the community. I hope Aki Nyrhinen chooses to contribute this
    work. If so, it looks as if the students here could contribute
    rate-scaling code for codecs with bad clocks, which seem to be
    common.

    As for the wasted-effort issue... I've been wary about
    pre-announcing student projects for a couple of reasons:

    1. They don't all pan out, so I'm not sure it would make
    sense to set up "leases" on unfilled holes in the code
    base--for six-month chunks of time.

    2. I think student projects benefit from not getting lots
    of "Is it ready yet? Can I help?" mail.

    Anyway, it looks like both the educational mission at CMU and
    the driver-development mission of the community have been
    served. I'm open to suggestions about how to possibly improve
    coordination... but meanwhile it's hard to argue with progress!

    Dave Eckhardt

+ Reply to Thread