Messages in this thread |  | | Date | Tue, 9 Oct 2001 14:27:46 -0500 (CDT) | From | Jeff Garzik <> | Subject | Re: [Emu10k1-devel] Re: Emu10k1 driver update |
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On Tue, 9 Oct 2001, Rui Sousa wrote: > On Tue, 9 Oct 2001, Jeff Garzik wrote: > 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...
Yep, that's how the via audio problem was solved, with a mixer semaphore. Having your interrupt handler touch ac97_codec definitely complicates things beyond that simple solution, though. If your only concern is the intr handler you could create a dont-touch-ac97-in-intr flag, and set that flag (only) via spin_lock_irq. Then you don't have to stay inside a spinlock the entire time.
Jeff
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