Re: More info on port 80 symptoms on MCP51 machine.

From: H. Peter Anvin
Date: Wed Dec 12 2007 - 16:10:33 EST


Rene Herman wrote:
On 12-12-07 21:26, Rene Herman wrote:

On 12-12-07 21:07, David P. Reed wrote:

Someone might have an in to nVidia to clarify this, since I don't. In any case, the udelay(2) approach seems to be a safe fix for this machine.

By the way, _does_ anyone have a contact at nVidia who could clarify? Alan maybe? I'm quite curious what they did...

Summary:

Unless after booting with "acpi=off", outputs to port 0x80 (the legacy way to delay I/O) reliably, but not immediately, hang MCP51 machines. Outputs to port 0xed do not indicating it's a not a generic bus abort problem.


Sorry, the first sentence didn't parse unambiguously for me. Do you mean "acpi=off" works, or that "acpi=off" allows *subsequent* boots to work?

I have some people at nVidia I can probably ping.

-hpa
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