Re: [PATCH] Disable i8042 checks on Intel Apple Macs

From: H. Peter Anvin
Date: Mon Jan 25 2010 - 16:33:20 EST

On 01/25/2010 08:34 AM, Vojtech Pavlik wrote:
> Thus I believe that the right fix here is to figure out why the accesses
> to the ports 0x60/0x64 take a long time or forever on a Mac. Is it just
> that the kernel is timing out waiting for the i8042? Or is it something
> more sinister?

In the A20 code in the setup code, I look for 0xFF coming back and
terminate the "wait for ready" loop much sooner than for other values.
0xFF is a *possible* status value, but not a very *likely* one
(especially for repeated reads), as it would represent:

parity error + receive timeout + transmit timeout + keyboard lock +
command + selftest OK + input full + output full.

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