[lkml]   [2001]   [Oct]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [Emu10k1-devel] Re: Emu10k1 driver update
    On Tue, 9 Oct 2001, Jeff Garzik wrote:

    Point taken.

    >From what I see doing locking with a spinlock is quite tricky.

    codec->read_mixer = ac97_read_mixer; //can be called holding spinlock
    codec->write_mixer = ac97_write_mixer; //can be called holding spinlock
    codec->recmask_io = ac97_recmask_io;
    codec->mixer_ioctl = ac97_mixer_ioctl; //in general can't be called
    holding spinlock

    and ac97_mixer_ioctl() itself calls ac97_read/write_mixer().

    A semaphore on the mixer device open function would do just fine If I
    didn't had an interrupt handler also touching the ac97_codec...


    > On Tue, 9 Oct 2001, Rui Sousa wrote:
    > > Actually there is no locking implemented for the ac97 codec mixer.
    > > It never seemed worth it, even if there are potential races in the code.
    > > To have two applications accessing the mixer at the same time is a _very_
    > > rare condition and the worse that can happen is to set a wrong volume
    > > value. Anyway, I will give it another look and try to come up with a fix.
    > I have a patch in the wings which adds locking to mixer accesses, for
    > via82cxxx_audio, because the lack of locking was causing problems. So,
    > some people with some apps do indeed notice...
    > Jeff
    > _______________________________________________
    > Emu10k1-devel mailing list

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:05    [W:0.023 / U:11.104 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site