Re: Flash Back -- kernel 2.1.111

Troy Benjegerdes (hozer@drgw.net)
Sun, 24 Feb 2002 15:19:23 -0600


On Sun, Feb 24, 2002 at 09:54:22PM +0100, Vojtech Pavlik wrote:
> On Sun, Feb 24, 2002 at 02:29:03PM -0600, Troy Benjegerdes wrote:
>
> > On Sun, Feb 24, 2002 at 01:18:33PM +0100, Martin Dalecki wrote:
> > > > Ummm, how does this work if I have two PCI ide cards, one on a 66mhz PCI
> > > > bus, and one on a 33mhz PCI bus?
> > > >
> > > > Or am I missing something?
> > >
> > > You are missing the fact that it didn't work before.
> >
> > What hardware, chipsets, situations, etc did the previous code not work
> > on?
> >
> > There is no avoiding the fact you need some kind of per-IDE controller
> > data for the clock for that particular PCI device.
>
> No. You don't need it. The base clock and multiplier are enough and you
> have the multiplier from PCI config.
>
> > I believe there are systems with 33mhz pci and 50mhz pci. Trying to find a
> > 'common' base clock just seems to be an excercise in confusion. The only
> > thing that really makes sense is 'how fast is said PCI device clocked'.
>
> Show me one.

There is one on my desk, using a gt64260 PowerPC bridge chip. It's got
dual PCI busses, and each can be clocked independently.

Table 2-6. System Clock Selection
CPU &
Memory Bus Fast/3V PCI Slow/5V PCI
Speed Bus Speed Bus Speed SW7 Settings
133 MHz 66 MHz 33 MHz 0100 0010
100 MHz 66 MHz 33 MHz 1111 1010
100 MHz 33 MHz 33 MHz 1010 1000
83 MHz 55 MHz 41 MHz 0111 1101
66 MHz 66 MHz 33 MHz 0101 0101
66 MHz 33 MHz 33 MHz 0000 0001

These is just a partial list of potential clock rates.

-- 
Troy Benjegerdes | master of mispeeling | 'da hozer' |  hozer@drgw.net
-----"If this message isn't misspelled, I didn't write it" -- Me -----
"Why do musicians compose symphonies and poets write poems? They do it
because life wouldn't have any meaning for them if they didn't. That's 
why I draw cartoons. It's my life." -- Charles Schulz
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