Okay... From your testing report:
This is behaviour consistent with the IRQ being dead ...
... and this isn't. Worse yet, we have a conflicting report from Michael
where things are fine while using aplay and I'm seeing nothing particularly
suspicious recently. I suppose it used to work and I suppose the behaviour
you are describing above is 100% repeatable?
Given that you can use aplay -- probably no difference with "aplay -M" ?
To get to the bottom of this we might need to get a specific failed version
(for readers, it's not been verified that this is a regression since 2.6.24)
but we can try to get lucky first.
The most recent change to sound/isa/es18xx.c that's not utterly impossible
to have made a difference is 1bc9eed379399484d3f5d5a0834674983969bc1,
"es18xx: Enable wavetable input from ESS chips". I don't know if you're a
GIT user. If you are, you can revert it simply with
$ git revert 1bc9eed3
If you're not a GIT user, applying the attached should work. Unlikely, but
as said, we can try.
Okay. A and B seem to at least confirm it's not the 16-bit DMA.
Rene.