Performances of open-source Radeon driver

I am the happy owner of a new netbook with an AMD Fusion E-450 APU, which includes a Radeon graphics card. I am using the open-source driver on it, that is a 3.2-rc7 kernel for KMS, and xserver-xorg-video-radeon package from sid. I have to say I am not really happy about the performances.

No I don’t speak about the graphical performances that are pretty good (especially compared to my Intel Atom N450 based previous netbook) but about the power consumption. With this setup and with the original battery I get 2h30 of autonomy. Switching to UMS and adding some power management options in xorg.conf improves it to 2h40, but breaks suspend to ram/disk (a pity for a netbook) and switch between VT. I then tried the non-free fglrx driver, it also suffers from the suspend to ram/disk issue, in addition to crashing xorg when playing videos… On the other hand I get an impressive 3h30 of autonomy, and additionally a silent netbook (contrary to the open-source driver, the fan doesn’t spin at idle).

I have tried plenty of options, ranging from adding some power management options to xorg.conf, to passing dynclks=1 to the radeon module, including setting /sys/class/drm/card0/device/power_method to dynpm. Right now I have worked around the issue by buying a bigger battery which brings me 5h30 of autonomy, but I would really appreciate any software way to improve it with the open-source driver.

6 Responses to “Performances of open-source Radeon driver”

  • Jonathan says:

    Just to check the obvious things: did you try setting power_method to low in sysfs? And have you tried asking on #radeon on freenode or for advice?

    • aurel32 says:

      Yes i tried all the possible values in syfs, i only mentioned the one that is supposed to get the best results. I also looked at the list of opened bug reports, but I haven’t tried yet to open a new one or ask on IRC.

      • paulez says:

        dypm is not the best solution in term of power consumption, because it changes only mem frequencies, the gpu one is the same as on high power profile.
        So with low settings you will have less power consumption because gpu will be down-clocked.

        • aurel32 says:

          dynpm actually does change the GPU frequencies, at least according to /sys/kernel/debug/dri/0/radeon_pm_info.

  • Chrisbee says:

    I’ve got an Acer Aspire 1 522 with the AMD fusion C50 chipset and I get ~6 hours autonomy on a bog standard Lubuntu 04-11 install. It’s got a 6 cell battery.
    Why not Debian? Squeeze comes up with 800 x 600 display resolution which sucks on a native 1280 x 720 display. Wheezy barfs during the install at the detect hard disks and partitions for some reason.
    I’m just a timid tinderer so don’t have the skills and confidence to poke further.

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