Mailinglist Archive: radeonhd (408 mails)

[Alex Deucher <alexdeucher@xxxxxxxxx>]

2009/6/9 Rafał Miłecki <zajec5@xxxxxxxxx>:
> 2009/6/5 Matthias Hopf <mhopf@xxxxxxx>:
> > After some discussion with AMD we found that there is a chance that with
> > only some additional AtomBIOS calls we might be able to get to the same
> > power levels as fglrx.
> >
> > With the following patch these are included, but only called if Option
> > "ForceLowPowerMode" is active. I'd like to have this tested before
> > I actually commit this. I tested it here and it *seems* to work -
> > I don't have a power meter at hand for validation at the moment.
> >
> > What we're still missing are
> > - PCIe lane changes
> > - Memory clock changes
> > - Dynamic clock changes
> > - Core voltage changes
> >
> > For all of them enough documentation is available already. So if *this*
> > patch actually helps reducing power consumption, we probably have enough
> > information for fully implemented power management.
> >
> > What we're still missing information for are
> > - Which clock/voltage settings are stable
> > - What is the minimum core / memory clock
> >
> > Maybe we'll find something by looking at the V4 version of the PowerPlay
> > AtomBIOS table (of which we currently don't know the details yet). Maybe
> > it helps smoking something while staring at the hexdumps =->>>
>
> I've some newbie questions.
>
> First of all, why do we use DynamicClockGating only for
> (rhdPtr->ChipSet < RHD_R600)? Is this enabled by default on everything
> newer than R600?

This table is empty on r6xx hardware.  The hw is different on r6xx and
newer asics.

> How does DynamicClockGating work? Does GPU knows itself all (unused)
> hardware blocks than he can stop clocking?

The GPU will turn off the clock to various blocks on the chip when
they are idle to save power.  When they are requested, they are
powered back up.  You can pick at the block level which blocks
participate or not.

> What actually is EnableASIC_StaticPwrMgt? Is this something we need to
> enable before using DynamicClockGating? If so, what other AtomBIOS
> commands depend on EnableASIC_StaticPwrMgt?

It enables automatic lower clocks for things like PCI D states.  I'm
not sure it makes much difference under normal circumstances.

> Could someone explain shortly other AtomBIOS commands like:
> ASIC_StaticPwrMgtStatusChange, DynamicMemorySettings, MemoryTraining

I'm not sure what the former is used for.  I suspect it's used when
changing power states.  The latter two are used for memory setup and
are called by other tables like SetMemoryClock or AsicInit.

Alex
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