Zaurus and sound

Last June I got a Zaurus PDA. IT runs Linux, and the idea is that I'll be able to use it for contact management, etc. If I can just get it talking.


But the sound driver crashes in audio_sync some times when the SNDCTL_SYNC IOCTL is issued. The kernel oopses and no more sound comes out. All very sad. And it's useless until I can fix this.

I finally got a chance to look at pxa-i2s.c in the Zaurus kernel sources. What complete crap. It seems like there is basically no locking in the code at all. I'm not completely convinced this is wrong for a uniprocessor machine, but the coding style does not inspire confidence so it will take me a while to reason about locking correctness. Here's a typical example of the style:

 if (b->offset &= ~3)  

I think that statement actually happens to be more or less correct, although it will sometimes lose a partial sample, but it brings new meaning to the word side effect. Hopefully I can figure out a solution to this problem before going to Japan. ( Read more... )