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SubjectRe: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.
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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