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

Alex Deucher alexdeucher at
Fri Apr 4 15:57:06 PDT 2008

On Thu, Apr 3, 2008 at 12:11 PM, Vedran Rodic <vrodic at> wrote:
> >
>  >  We have plans to support it in the free drivers, we just haven't
>  >  gotten around to it yet.   There are several aspects to powerplay,
>  >  some are driver controlled others are hw controlled.  Some of the hw
>  >  controls can already be implemented based on the documentation we've
>  >  released, it's just that no one has done it yet.  The rest will come
>  >  eventually.
>  >
>  But the documentation is lacking: We only have a list of registers
>  without really knowing which ones we can touch, and we also don't know
>  any details of how they work together, on what versions of hardware
>  etc.
>  I have a rv670, and I just assumed that the rv620 documentation
>  applies for it too. I wanted to be able to control the clock (to
>  downclock the GPU since I've noticed that Windows does that and that
>  my GPU cooler is a lot less warmer in Windows). But it's really hard
>  to understand clock and power management registers just by a brief
>  list and a really insufficient explanations on the rightmost column.
>  I've tried setting the GLOBAL_PWRMGT_EN bit in GENERAL_PWRMGT register
>  (while turning off STATIC_PM_EN bit because it seemed logical), and I
>  got flying animated garbage as a result.
>  On the other hand, I've enabled DYNAMIC_GFX_ISLAND_POWER_DOWN and
>  DYNAMIC_GFX_ISLAND_LP in SCLK_PWRMGT_CNTL without any readily visible
>  side effects.

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.


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