Using VESA to restore display settings on resume

Josh Elsasser josh at elsasser.org
Mon Feb 28 04:24:34 GMT 2005


On Mon, Feb 28, 2005 at 02:11:58AM +0300, Vladimir Grebenschikov wrote:
> ? ??, 27/02/2005 ? 16:16 -0500, 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.
> 
> 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.

What is hw.acpi.reset_video set to on your system?  At some point
between 5.2 and 5.3, my machine would hang on resume instead of just
resuming with no display.  Setting hw.acpi.reset_video=0 in
loader.conf fixed that.  I have a Sony Vaio FX220, which has an i815
graphics chip.

 -jre
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