Using VESA to restore display settings on resume

Vladimir Grebenschikov vova at
Mon Feb 28 07:38:36 GMT 2005

В вс, 27/02/2005 в 16:16 -0500, Josh Elsasser пишет:
>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:
>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
>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.

What notebook you have ? I was not such lucky.

I Has SONY VAIO PCG-Z1WA, by zzz it sleeps ok, 
With patch it even said about saving VESA data.
On any key after it is awakes, spin up drive and fan, but screen still
black (even no backlight), and it is very unlike that I get console back
(typing has no effect, even when I try to call kdb).

Also if I try this patch with vesa module loaded it just carsh in vm86
mode on zzz (curproc acpiconf).

Any suggestions are very welcome.

>I would love to see this committed and MFC'd if it doesn't break
>things for anyone else.
> -jre
Vladimir B. Grebenchikov
vova at

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