idebus=133 ?

Tom Rini trini at
Mon Oct 22 12:56:58 EST 2001

On Sun, Oct 21, 2001 at 03:42:11PM -0700, Dave Ray wrote:

> It's my understanding the Mac G4 towers run at a bus
> speed of 133 MHz. However the kernel argument for
> idebus=xx apparently only allows values up to 66. Is
> this intentional?

idebus != 'bus'.  The 133 referrs to the speed the memory and cpu can
talk at.  Your idebus setting shouldn't change from the default.
>From Documentation/ide.txt:
"idebus=xx"            : inform IDE driver of VESA/PCI bus speed in MHz,
                                where "xx" is between 20 and 66 inclusive,
                                used when tuning chipset PIO modes.
                                For PCI bus, 25 is correct for a P75 system,
                                30 is correct for P90,P120,P180 systems,
                                and 33 is used for P100,P133,P166 systems.
                                If in doubt, use idebus=33 for PCI.
                                As for VLB, it is safest to not specify it.
                                Bigger values are safer than smaller ones.

Tom Rini (TR1265)

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