Using VESA to restore display settings on resume

[Josh Elsasser]

On Sun, Feb 27, 2005 at 04:31:25AM +0000, Ian Dowse wrote:
> 
> It's possible that the experimantal patch below may help on some
> notebooks where the display does not recover from a suspend-resume
> cycle. It makes use of the VESA BIOS to save the display settings
> before the system suspends and then restores them on resume. The
> patch is against -CURRENT, but might apply against RELENG_5 without
> too much trouble.
> 
> I have a JVC laptop here where this is the only way I have found
> so far to bring the LCD back to life after resuming, so maybe it
> will help on other systems too.
> 
> To test it, apply the patch and rebuild your kernel + modules. You
> need to either have 'options VESA' in the kernel config or else
> load the vesa module. It may also be worth trying with the
> hw.acpi.reset_video sysctl set to 0, since rerunning the VGA POST
> should be unnecessary.
> 
> Ian
> 
> Patch also at: http://people.freebsd.org/~iedowse/vesa_restore.diff
> 

THANK YOU!  I've had my laptop for 3 1/2 years, and I can finally
suspend/resume and have a usable display afterwards!  Cardbus doesn't
appear to work after resume, but that's a whole different can of
worms...

The system I tested this on was RELENG_5 from yesterday, the patch
applied cleanly.  I already had the hw.acpi.reset_video set to 0, so I
don't know if it would work with it set to 1.

I would love to see this committed and MFC'd if it doesn't break
things for anyone else.

 -jre
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