Video PM Methods

[Stefan Seyfried]

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

> 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.

> 5. vbetool dpms suspend  <and> vbetool dpms on
> 6. radeontool?
> 
> How do we handle the kernel parameters? Should we check the grub
> commandline to make sure we have the correct parameters and fail to
> suspend the video if not set correctly?

not needed, see above.

> 
> 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)
> 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?
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.

The "vbemode get/set" part is not yet committed to CVS but trivial enough
and will be added soon.

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.
-- 
Stefan Seyfried                  \ "I didn't want to write for pay. I
QA / R&D Team Mobile Devices      \ wanted to be paid for what I write."
SUSE LINUX Products GmbH, Nürnberg \                    -- Leonard Cohen