Radeon HD 3670 and power saving (Dynamic Clocks?)

[VinzC]

Hi all.

I'm the lucky owwner of a laptop (Dell XPS Studio 16) with an ATI Radeon HD 3670. I've tried ATI proprietary drivers but had to switch -- reason number 1 is I'm now with kernel 2.6.30-gentoo-r1 -- I'm running Gentoo Linux BTW.

While I was using that driver I noticed my battery lasted at least 2 hours with ATI/AMD power saving option checked (don't remember the exact name). Now I'm using radeon Open Source driver it only lasts 1 hour and a half... (Option "DynamicClocks" is set to "On" in xorg.conf.)

Did anybody succeed in having the battery last the same as with fglrx?

Thanks in advance.

[bridgman]

Can you try ForceLowPowerMode ? You'll need a relatively recent radeon driver.

I don't think DynamicClocks (now called ClockGating IIRC) does anything on 6xx and higher, not 100% sure though.

You should also check the log to make sure DynamicCLocks is even being accepted by the driver. On recent drivers that option was renamed to ClockGating IIRC.

[VinzC]

I'm using x11-drivers/xf86-video-ati-6.12.2. Should I retrieve the most recent one from GIT or so? I have no such option ClockGating, BTW. I do have an option ForceMinDotClock -- I'm reluctant to use it as per the man page (can damage the hardware).

# egrep -i 'dynamic[[:space:]]*clocks?' /var/log/Xorg.0.log
(**) RADEON(0): Option "DynamicClocks" "On"
Dynamic clock gating enable success
Dynamic clock gating enable success

Looks like dynamic clocks are accepted.

EDIT: There's no such option "ForceLowPowerMode". BTW if I enable that option, won't the card work under low power all the time even when running on mains?

[bridgman]

Power management went in right after the 6.12.2 release, so you will need to pull more recent code from git.

Yes, ForceLowPowerMode will run under low power / speed all the time even on mains, but normally you don't notice much difference. Dynamic power management really needs to be implemented in the kernel, not the usermode driver, and that won't happen for a while yet.

[VinzC]

Power management went in right after the 6.12.2 release, so you will need to pull more recent code from git.

Yes, ForceLowPowerMode will run under low power / speed all the time even on mains, but normally you don't notice much difference. Dynamic power management really needs to be implemented in the kernel, not the usermode driver, and that won't happen for a while yet.

Thank you for the information. I've just read on Phoronix that David has just added code to the driver for later use when the kernel module gets ready. I think I'm going to wait a little -- I'm not [yet] in a hurry.

Thanks again.