DMA IRQ, or How To Prevent ipaq-sleep From Suspending A Zaurus Playing Music

I've been searching for a while for the "official" way to stop 
ipaq-sleep from suspending my boxer while it was playing music (with 
mplayer).  Searching in the forums, on the wiki and with google only 
resulted in hacks I didn't like (e.g., wrapping mplayer in a script 
which stops and restarts ipaq-sleep).  I suspected I could use the IRQ 
parameter in ipaq-sleep configuration to solve the problem, but I wasn't 
able to find in /proc/interrupts an IRQ related to audio.  Yesterday I 
did some tests, and found out that setting IRQ = 18 in 
/etc/ipaq-sleep.conf works, namely, prevents suspending while playing 
music (and only when playing music, at least so far).

Now, looking back in /proc/interrupts i found that IRQ 18 belongs to 
DMA.  I can imagine why this works, but still:

- does anybody foresee any possible problems (i.e., unwanted blocks of 
suspending)?

- why there is no IRQ for the audio system (which would give a far more 
elegant solution)? Does this depend on the OZ hardware?

Having this answer, I would gladly write this piece of info in the wiki 
  / in the FAQ / wherever, since I am not the only one to look for such 
a solution.

Thanks,
Francesco.

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