Messages in this thread | | | Date | Tue, 8 Jan 2008 13:51:47 +0100 (CET) | From | Bodo Eggert <> | Subject | Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. |
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On Tue, 8 Jan 2008, Rene Herman wrote: > On 08-01-08 00:24, H. Peter Anvin wrote: > > Rene Herman wrote:
> > > Is this only about the ones then left for things like legacy PIC and PIT? > > > Does anyone care about just sticking in a udelay(2) (or 1) there as a > > > replacement and call it a day? > > > > > > > PIT is problematic because the PIT may be necessary for udelay setup. > > Yes, can initialise loops_per_jiffy conservatively. Just didn't quite get why > you guys are talking about an ISA bus speed parameter.
If the ISA bus is below 8 MHz, we might need a longer delay. If we default to the longer delay, the delay will be too long for more than 99,99 % of all systems, not counting i586+. Especially if the driver is fine-tuned to give maximum throughput, this may be bad.
OTOH, the DOS drivers I heared about use delays and would break on underclocked ISA busses if the n * ISA_HZ delay was needed. Maybe somebody having a configurable ISA bus speed and some problematic chips can test it ...
-- Fun things to slip into your budget "I [Meow Cat] sliped in 'Legal fees for firing Jim (Jim's my [his] boss).' Jim approved the budget and was fired when upper management saw the budget."
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