X.Org ATI Driver Supports New Power Options
Phoronix: X.Org ATI Driver Supports New Power Options
Besides seeing 3D acceleration for their hardware in an open-source driver, one of the other leading requests from ATI Radeon customers has been to see improved power management within the ATI X.Org driver stack. There is Dynamic Clocks support and some other power management capabilities, along with some more innovative ways, but ATI's PowerPlay is not fully implemented in the open-source stack...
1. Why isn't DynamicClocks enabled by default?
2. What's the need for ForceLowPowerMode, when DynamicPM does the same but only when necessary?
3. Why should DynamicPM decrease performance?
ForceLowPowerMode can be useful, if you are in batterie mode; even though it's use get's lost, as you can't dynamical change the Mode. That DynamicPM decreases performance is a common bias against any power management (and is plain wrong).
Maybe R600+ have other power management features, so this is how it is done one R100-R500 ?
Very cool that power management begins to be supported!
The DynamicPM option shouldn't affect performance. It only switches to a low power mode during idle (DPMS active). When you are using the system, it switches back to the default power mode.
@agd5f: What does idle mean in this case? Since it's somehow connected to dpms I guess something like display is turned off/in standby?
Or does it in fact react on gpu-load? And if so, would e.g. Compiz trigger a higher performance mode?
These are very good news. I've been changing between fglrx and radeon since always and since I don't play any games in linux this can be what will enable me to ditch fglrx for good.
You also get lower performance in fglrx when you enable a power save mode. It has no real impact when watching films or under normal usage; you notice it when you measure the fps of some 3D application. I always use the laptop in lower power mode unless I explicitly tell it not to do so, and everything is fine.
At the moment, this doesn't work for me. With activated DynamicPM option, the card always uses the lowest possible mode. But perhaps this isn't the right place for bug reports and of course it's still development code.
Originally Posted by agd5f
But nevertheless thank you for bringing power management to R700 based cards on linux! This saves nearly 17W for me in regular system operation, since the Radeon 4670 is only actually powersaving when those powerplay features are activated.