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

From: Ingo Molnar
Date: Mon Dec 17 2007 - 16:57:52 EST



* Rene Herman <rene.herman@xxxxxxxxx> wrote:

>>> Signed-off-by: Rene Herman <rene.herman@xxxxxxxxx>
>>
>> hm, i see this as a step backwards from the pretty flexible patch
>> that David already tested. (and which also passed a few hundred
>> bootup tests on my x86 test-grid)
>
> Please see Alan's comment that udelay (and none) shouldn't yet be
> provided as a choice. It opens race windows in drivers even when it
> works in practice on most setups. The version with "udelay" and "none"
> is not minimal, not low risk and certainly not .24 material.

huh? By default we still use port 0x80. Any udelay is non-default and
needs the user to explicitly switch to it. But it enables us to debug
any suspected drivers by asking testers to: "please try this driver with
io_delay=udelay, does it still work fine?". So those extra options are
quite sensible. If you have any real technical arguments against that
then please let us know.

Ingo
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