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    SubjectRe: ANNOUNCE: big change in PCM kernel API
    Alan Cox wrote:
    >
    > > The only drawback is that the maximum number of pcm devices for card is
    > > decreased to 8 from 16, but this will change when linux kernel will use
    > > a wider kdev_t.
    > >
    > > Obviously the OSS emulation behaviour is intact.
    >
    > The OSS API appears to be making a subtle change for 2.4, not one I planned
    > but one that several groups arrived at and which I can't find an application
    > that breaks from.
    >
    > On the new trident driver and on the SB Live! driver opening /dev/dsp gets
    > you a new free channel if there are any free channels on the card.
    >
    > Both drivers get the locking wrong right now (hint - need to drop the inode
    > lock as they share the inode and one sleeping on a write locks out the other)
    > but the API change seems sane and I think we should tweak other cards with
    > many channels to do the same (eg the ESS Maestro)
    >
    > Views from the ALSA side ?
    >
    > Alan

    ALSA has already the same behaviour (also for OSS emulation) and the
    inode lock is dropped on write (to tell you the truth I'd have preferred
    that sys_write transfer the inode->i_sem handling entirely to
    f_op->write, but probably the efficiency impact of the double down/up is
    small)

    I'm not sure to understand the second part (and one sleeping on a write
    locks out the other), can you rephrase that?

    --
    Abramo Bagnara mailto:abramo@alsa-project.org

    Opera Unica
    Via Emilia Interna, 140 Phone: +39.0546.656023
    48014 Castel Bolognese (RA) - Italy Fax: +39.0546.656023

    ALSA project is http://www.alsa-project.org
    sponsored by SuSE Linux http://www.suse.com

    It sounds good!

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