A New Patch For Radeon DRM Power Savings

[barkas]

In case of my HD 34x0 engine downclocking gave quite nice result already. I did not see much difference when downclocking memory. Not sure what voltage changing will bring. Maybe not much difference to temperature, but some to battery life time?

I really hope to get engine downclocking commited for 2.6.33-rc1. Hopefully Alex will release IRQs before that, so I will able to enable memory downclocking as well for 33-rc1.

heat ~ clock * voltage^2

So voltage should bring more benefit than clock adjustment.

[Zajec]

actually this patch is just a first attempt at dynamic power management. It may still take some time until there is something usable in trunk...

However before GPU voltage can be dynamically changed I wouldn't think it can help R600 to cool down much.

In case of my HD 34x0 engine downclocking gave quite nice result already. I did not see much difference when downclocking memory. Not sure what voltage changing will bring. Maybe not much difference to temperature, but some to battery life time?

I really hope to get engine downclocking commited for 2.6.33-rc1. Hopefully Alex will release IRQs before that, so I will able to enable memory downclocking as well for 33-rc1.

[FunkyRider]

This is very interesting and useful function, especially for the hi-end big ass GPUs. For my 2900XT, you don't only feel the speed, you can 'Hear' it. If the fan does not revs up all the time using this Power Management code, that's a fantastic thing. I will be more than willing to test it on my 2900XT since it is the worst 'Heater' on the R6/7/8 family so far. However before GPU voltage can be dynamically changed I wouldn't think it can help R600 to cool down much.

Keep up the good work!

[legume]

Great. That just leaves Zaphod mode, which wasn't working the last time I checked. Then I can finally switch!

Of course according to the officially snactioned recent sequel to hhg Zaphod doesn't have two heads anymore - left brain lives in a jar :-)

[madman2k]

Great. That just leaves Zaphod mode, which wasn't working the last time I checked. Then I can finally switch!

actually this patch is just a first attempt at dynamic power management. It may still take some time until there is something usable in trunk...

[Pfanne]

one step closer to a fully opensource notebook
great job!

edit:
why did this thread end up in the intel open source section?

[Chewi]

actually it only works with KMS

Great. That just leaves Zaphod mode, which wasn't working the last time I checked. Then I can finally switch!

[madman2k]

Does this stuff work with KMS?

actually it only works with KMS

[Chewi]

Does this stuff work with KMS?

[Louise]

That's really perfect summary. Patch itself is quite simple but I had many problems to get it working. First I had to learn about timers (there are many kinds of timers in kernel, some with limitations). Experienced about 50 locks up when fighting with that one. Then I tried to use ring info to determine GPU load. This didn't work so I had to switch to fence (again, learning what fence is...).

It is scary to think about how much time that goes into coding that the programmer doesn't get credit for

But hopefully I have now more idea about driver stuff and will able to do rest faster

I read the reply on the mailing list. What will you next step be?

Figure out the API to ask if the GPU is idle?
Only downclock if vblank?