Video PM Methods

[Richard Hughes]

On Tue, 2006-05-16 at 20:30 +0200, Stefan Seyfried wrote:
> On Tue, May 16, 2006 at 05:54:34PM +0100, Richard Hughes wrote:
> > Right, lets re-open the discussion:
> > 
> > I agree having three types of video card (ati, nvidia, intel) was
> > probably over-generalising the quirks needed and we need finer-grained
> > control for some videocards.
> > 
> > To resume from video suspend we may have to use (one or many of):
> > 
> > 1. S3_BIOS kernel boot option
> > 2. S3_MODE kernel boot option
> 
> This can be set in /proc/sys/kernel/acpi_video_flags

Cool, thanks. Any idea what to echo for each case as I just have "0" in
that file.

> > 3. vbetool post
> > 4. vbetool vbestate save <and> vbetool vbestate restore
> 
> often "X=`vbetool vbemode get`" and "vbetool vbemode set $X" is enough, and
> considered less intrusive.

Okay, thanks.

> > How do we specify, for instance, that my intel video card needs to do:
> > 
> > vbetool vbestate save
> > vbetool dpms suspend > foo
> > <suspend>
> > vbetool dpms on
> > vbetool vbestate restore < foo
> > 
> > How about:
> > 
> > video_adapter_pm.vbe_state_restore (bool)

So:

video_adapter_pm.vbe_restore would be a better name so that we could use
restore and save or get and set to do the same thing?

> > video_adapter_pm.vbe_post (bool)
> > video_adapter_pm.dpms_force (bool)
> 
> > But then the methods are present on the computer node, not the display adapter (problem?).
> > 
> > Anyone got any good ideas?
> 
> just use s2ram?

I really want to use fdi-matches, rather than a compiled black/white
list. Also using HAL scripts, all this is easy to do with little shell
scripts without any new deps.

> If you do not like the built-in blacklist (i am also not too happy
> with it), you can still call "s2ram -f --acpi_sleep=3 --radeontool" or 
> whatever, depending on what you found out from your fdi matches.

Surely it's easy enough to just add it directly to a small
hal-system-foo bash script?

> Oh - and some machines will only resume from RAM when running on VGA console
> or vga16fb, but not on vesafb or any other framebuffer, many newer DELLs and
> HPs with ATI cards are prominent examples.

Hmm.. how do we work round this other than setting vga= stuff on the
kernel command line?

Richard.