AMD/ATI PowerPlay-Support in radeon(ati) or radeonHD?

Alex Deucher alexdeucher at
Mon Apr 7 15:19:29 PDT 2008

On Mon, Apr 7, 2008 at 2:17 PM, Vedran Rodic <vrodic at> wrote:
> On Sat, Apr 5, 2008 at 2:49 PM, Vedran Rodic <vrodic at> wrote:
>  > >  I've just added atombios support for the "DynamicClocks" option on
>  >  >  r5xx/r6xx cards to the radeon driver.  It should enable dynamic clock
>  >  >  gating and static power management if the chip supports it.  This is
>  >  >  not full powerplay support, just one aspect.  Also, the bios may set
>  >  >  some or all of this up at post so, YMMV.
>  >  >
>  >
>  >  Great, thanks.
>  >
> >  fglrx driver is definitely doing something on rv670.  I still haven't
>  >  tested the power usage with "ati" driver though, but will later today.
>  >
>  Unfortunately, this option doesn't work for HD3850, it doesn't save
>  power. Also VT switch tends to lockup the machine, try to do it a
>  couple of times and it surely will. It also doesn't detect all the
>  video modes (higher resolutions and refresh rates). GIT version from
>  today, Xserver xserver-xorg-core
>  (1.4.1~git20080131-1ubuntu6).

I put a rough cut of the initial powerplay support in my personal tree here:
it's builds on Dave's previous tree.  from the commit log:

Support for adjusting sclk, mclk, and pcie lanes. pcie lane support is
commented out at the moment as the results are a bit tweaky on my box.
If you try it let me know how it goes. voltage support and version 4.x
powerplay tables are not yet supported. To enable powerplay, load the
driver and it will print out the power modes that are available.
Select one of the modes enable it my adding: Option "PowerPlayMode"
"mode" to the device section of your config. This can be done on the
fly, but at the moment, there's not really a good interface for this
(randr gpu objects eventually).


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