On Wed, 2006-05-24 at 08:15 +1000, Benjamin Herrenschmidt wrote: > > Right, that's how snd-powermac does it. It has the nasty side-effect of > > polluting the cache a lot though, since dbdma commands are 16 bytes > > long. Am I wrong? > > You don't have that much DBDMA commands that it would pollute the cache > _a lot_ :)
Ah, yeah, I guess so. Well I do have 32 dbdma commands, them being spaced up in 16-bytes means 16 cachelines, no? I'm not sure how the cache is wired up ... > > Alsa calls this thing the 'pointer' :) The frame counter we currently > > use is the frame counter register of the i2s bus controller, and I don't > > see why we shouldn't do that instead of reading back all the dbdma > > command status fields. > > If you manage to have it properly in sync, that may work too. Seems to work fine so far, even if bcm43xx kills a few interrupts ;) johannes
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