Messages in this thread | | | Date | Sat, 08 Jan 2000 23:26:04 +0100 | From | Abramo Bagnara <> | Subject | Re: ANNOUNCE: big change in PCM kernel API |
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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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