sleepable delays from kernel code.

[Iain Sandoe]

Hi,

It would be very useful to have a "sleepable" kernel delay function with
better resolution than 10ms for some of the sound stuff.  10 or 100 us
resolution would be helpful.

This is because power-up/down (and some register accesses) of some of the
audio devices takes quite some time.

Also, it seems, that the keywest-i2c device only works in polled mode at the
moment (?? don't know if this is a real hardware fault or just waiting for a
fix).

To my mind there are too many u/mdelay() calls in the sound code at the
moment and I would like to replace as many as possible/appropriate with
sleeps on a timer.

any ideas how best to improve the resolution?

e.g.

increase HZ (could we stand a higher rate on PPC? - IIUC Alpha uses 1024)

add a front end into arch/ppc/kernel/time.c that exports a high(er)
resolution timer callback?

any help would be appreciated.
ciao,
Iain.

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