Messages in this thread | | | Date | Mon, 25 Jan 2010 14:15:20 -0800 | From | Dmitry Torokhov <> | Subject | Re: [PATCH] Disable i8042 checks on Intel Apple Macs |
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On Mon, Jan 25, 2010 at 01:32:42PM -0800, H. Peter Anvin wrote: > 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. >
You allow up to 32 0xFFs while i8042 driver does maximum 16 reads of whatever - if OBF is still raised we assume i8042 is not there. Does that mean that reads from 0x60 is what hurts on Macs?
Bastien, could you try modifying drivers/input/serio/i8042.c:: i8042_flush() to not call i8042_read_data() when str is 0xff and see if it helps with lockups?
Thanks.
-- Dmitry
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