On Sat, Dec 25, 2010 at 7:02 PM, Peter Lieven <pl@xxxxxxx> wrote:
> this was the outcome of my bisect session:
>
> 956a3e6bb7386de48b642d4fee11f7f86a2fcf9a is first bad commit
> commit 956a3e6bb7386de48b642d4fee11f7f86a2fcf9a
> Author: Blue Swirl <blauwirbel@xxxxxxxxx>
> Date: Sat May 22 07:59:01 2010 +0000
>
> Compile pckbd only once
>
> Use a qemu_irq to indicate A20 line changes. Move I/O port 92
> to pckbd.c.
>
> Signed-off-by: Blue Swirl <blauwirbel@xxxxxxxxx>
>
> :100644 100644 acbaf227455f931f3ef6dbe0bb4494c6b41f2cd9 1a33d4eb4a5624c55896871b5f4ecde78a49ff28 M Makefile.objs
> :100644 100644 a22484e1e98355a35deeb5038a45fb8fe8685a91 ba5147fbc48e4faef072a5be6b0d69d3201c1e18 M Makefile.target
> :040000 040000 dd03f81a42b5162c93c40c517f45eb9f7bece93c 309f472328632319a15128a59715aa63daf4d92c M default-configs
> :040000 040000 83201c4fcde2f592a771479246e0a33a8906515b b1192bce85f2a7129fb19cf2fe7462ef168165cb M hw
> bisect run success
Nice job bisecting this! I can reproduce the Memtest86+ V4.10 system
reset with qemu-kvm.git and qemu.git.
The following code path is hit when val=0x2:
if (!(val & 1)) {
qemu_system_reset_request();
}
I think unifying ioport 0x92 and KBD_CCMD_WRITE_OUTPORT was incorrect.
ioport 0x92 is the System Control Port A and resets the system if bit
0 is 1. The keyboard outport seems to reset if bit 0 is 0.
Here are the links I've found describing the i8042 keyboard controller
and System Control Port A:
http://www.computer-engineering.org/ps2keyboard/
http://www.win.tue.nl/~aeb/linux/kbd/A20.html
Blue Swirl: Any thoughts on this?
Stefan
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