Re: [PATCH] reset VGA adapters via BIOS on resume...(non-fbdev/con)

[Alan Cox]

On Sad, 2005-07-23 at 00:17 +0100, Matthew Garrett wrote:
> Dave Airlie <airlied@xxxxxxxx> wrote:
> 
> > 	At OLS at lot of people were giving out about cards not resuming,
> > so using a patch from Michael Marineau and help from lots of people
> > sitting around in a circle at OLS I've gotten a patch that restores video
> > on my laptop by going into real mode and re-posting the BIOS during
> > resume,
> 
> On laptops, the code at c000:0003 may jump to BIOS code that isn't
> present after system boot. In userspace, this isn't too much of a
> problem - the userspace code tends to just fall over rather than hanging
> the machine. What happens if the kernel hits illegal or inappropriate
> code on resume?

For Intel at least the recommendation is to use the BIOS "save
mode"/"restore mode" interface.

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