[PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic

Ingo Molnar mingo at elte.hu
Wed Jan 26 07:58:13 EST 2011

* Ahmed S. Darwish <darwish.07 at gmail.com> wrote:

> - The latest approach (proposed by Linus) is to forget the disk: jump to
>   real-mode, but display the kernel log in a fancy format (with scroll
>   ups and downs) instead.
>   Will re-initializing the VGA registers to their POST state be possible?
>   If not, what about a "fail-safe" VGA driver?
> I'm most likely going to implement either the second or the third point,
> so I'd really appreciate some input.

The third one suggested by Linus is the most useful and most direct one IMO. Such a 
'oops mode' screen would be useful for regular kernel crashes as well.

Also, have you tried BIOS warm reset vector, which is supposed to reboot without 
clearing RAM contents - how well does it work in practice on typical laptops? If on 
crash we could reboot without memory getting cleared that would open up a vast area 
of space to store the kernel log into (RAM).



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