Christer Weinigel <[EMAIL PROTECTED]> wrote: > How do you find out the speed of the ISA bus? AFAIK there is no > standardized way to do that. On the Geode SC2200 the ISA bus speed is > usually the PCI clock divided by 4 giving 33MHz/4=8.3MHz or > 30/4=7.5MHz, but with no external ISA devices it's possible to > overclock the ISA bus to /3 to run it at 11MHz or so. But without > poking at some CPU and southbridge specific registers to find out the > PCI bus speed and the ISA bus divisor you can't really tell.
If you overclock, you are on your own. IIRC I've used 13,3 MHz for some time and used a lower PIO mode to compensate. > So if you do udelay based on a 6MHz clock (I think you can safely > assume that any 386 based system runs the ISA bus at least that fast) > you'll waste at least 30% and maybe even 100% more time for the delay > after every _p call. Defaulting to 8 MHz and offering an option to set another clock speed (like idebus=) should be OK. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
