Boot halts on Thinkpad X220 (Sandy Bridge)

[Xin LI]

On Thu, May 19, 2011 at 5:18 AM, Johannes Dieterich
<dieterich.joh at googlemail.com> wrote:
> On Wed, May 18, 2011 at 7:40 PM, Xin LI <delphij at delphij.net> wrote:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA256
>>
>> Try this patch?
>>
> The attached patch makes 9-CURRENT-amd64 boot on the X220 w/o any hints or
> BIOS fixes needed. Thanks a lot! :-)
>
>
>
>>
>> (I'm still opted to disable the typematic rate detection by default at
>> least for amd64, as we don't do it in the past for amd64)
>>
> What does this mean concerning getting the fix into CURRENT?

Well, that's not a perfect fix and we do lose the ability of detecting
typematic rate (by default), so technically it's a workaround
(sufficient to make the kernel boot and work, though) and doesn't fix
anything.

I have committed it anyway since we do not have better fix (yet), and
have updated atkbd(4) manual page so one can enable it again when
wanted.

The problem we had was that it seems that running the BIOS in the
x86emu emulator on amd64 would cause problem.  This doesn't seem to be
fixable without hands-on experiments on a system in question, it's
either a BIOS bug or an emulator bug.  The strange part of the problem
is that the functionality is quite common in the Good Old Days (TM).

Cheers,
-- 
Xin LI <delphij at delphij.net> http://www.delphij.net