No DPMS for Console on x86_64

No DPMS for Console on x86_64

[Thomas Zehetbauer]

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Unfortunately it seems that setterm's powersaving (DPMS) capabilities depend 
an APM support in the kernel and are therefore unavailable on the x86_64 
architecture.

This shortcoming may have seemed unimportant when Opteron started in the 
server segment but there is a growing number of AMD Turion mobiles that could 
greatly benefit from this feature.

I wonder how difficult it would be, to port APM to the x86_64 architecture or 
to provide DPMS support in the FBDev drivers.

Tom

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Re: No DPMS for Console on x86_64

[Jan Engelhardt]

>
> Unfortunately it seems that setterm's powersaving (DPMS) capabilities depend an
> APM support in the kernel and are therefore unavailable on the x86_64
> architecture.
>
> This shortcoming may have seemed unimportant when Opteron started in the server
> segment but there is a growing number of AMD Turion mobiles that could greatly
> benefit from this feature.
>

There are some backlight drivers in the kernel. Currently however the only 
supported device is Sharp Corgi.
Would it be possible to make DPMS signalling a backlight driver? (Without 
the APM overhead.) vgacon for example leaves the backlight on while in X11, 
DPMS is enabled and signals standby after the timeout.


Jan Engelhardt
-- 

Re: No DPMS for Console on x86_64

[Andi Kleen]

Thomas Zehetbauer <thomasz@hostmaster.org> writes:
> 
> I wonder how difficult it would be, to port APM to the x86_64

Modern systems generally don't have working APM anymore.
There are replacement ACPI video options, but they seem to 
be rarely implemented because the system vendors assume the
video driver will do the job.

Also even if they had it wouldn't be implemented in the 64bit
kernel.

> architecture or to provide DPMS support in the FBDev drivers.

There is some code from PPC for that, but it is generally very 
PPC specific. Backlight control also varies a lot so it would
likely need tweaks for most laptops.

Or just run a X server. It also doesn't get this right always, but
at least sometimes.

-Andi