On Sat, Mar 30, 2002 at 01:57:12PM +0100, Fran?ois Cami wrote:

> Vojtech Pavlik wrote:
> > Hi!
> > 
> > I think it should be possible to make the ICH2 and ICH3 Intel chips
> > (82801BA and 82801CA) do UDMA133. (Intel only says they can do UDMA100).
> > If anyone running a 2.5 kernel with an Intel mainboard with one of those
> > chips and a UDMA133 capable harddrive is willing to test this, please
> > contact me, I'll give you a patch.
> 
> I'm in.
> i815ep (tusl2-c mainboard) + maxtor 80GB udma 133.
> 
> I'm wondering how you can do that though... Would you
> explain, please ?

The ich2/3 use a 133 MHz base clock for IDE timing. And have a divisor
settable, they divide by three to get 50 MHz base clock for UDMA100
(it's 16-bit), and can divide by two to get 66 and hence UDMA133.
However that value (division by 2 with 133 MHz clock) is marked as
'reserved' in the specs.

In the end it may or may not work. I'm very curious, though.

VERY untested patch attached.

-- 
Vojtech Pavlik
SuSE Labs