Re: [iPAQ] Ipaq Pcmcia 2fast4you ?

On Tuesday, April 17, 2001, at 03:21 PM, tytso@thunk.org wrote:

> So was this a bit of lore that everyone else knew? Was I just
> unlucky? Also, does this work by actually slowing down the CPU? If
> so, it seems kinda a lose that I'm going to have to slow down the
> (already not-terribly-blazing-fast) ARM processor just to keep the
> PCMCIA card happy.

If it is genuinely necessary to slow down the core clock on the iPAQ
just to make PCMCIA devices work, then that indicates a hardware bug.
What's more likely is that the kernel is failing to set up the hardware
properly.

I haven't looked at the clock scaling driver, but it's worth stating
that any change in the core frequency _must_ be accompanied by a change
to the various fields in the MECR (card interface timing register). The
SA-1100 PCMCIA socket driver properly configures this register in an
implementation-independent manner, but as of the last time I touched it,
it contained no provision for scaling.

-jd
Received on Tue Apr 17 13:09:28 2001