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State of Powerplay on R500

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  • State of Powerplay on R500

    After switching to xorg-server-1.5.3 on gentoo, I have made the horrible discovery that NONE of the driver versions that work with 1.5.3 support powerplay on my mobility X1300 (on a Thinkpad T60) anymore (which has worked for me flawlessly in the past). Trying to change the powerstate completely garbles the display and hardlocks the system most of the time. Even worse, trying to start X while on battery equally hardlock the system, making it impossible to boot on battery.

    I have managed to work around this by setting the key DALPowerPlayOptions=V0 in /etc/ati/amdpcsdb which seems to completely disable powerplay. However, as this is a laptop, disabling powerplay is not really an option. So: has anybody encountered the same problem and found a proper fix? Or, even better, is there any statement from the official side (bridgman) on whether this is a known bug and will be fixed?

    I would love to use the opensource driver as an alternative but, unfortunately, it is currently unable to vsync and doesn't improve things battery-wise (together with slower rendering).

  • #2
    When you say "the open source driver is unable to vsync" do you mean for GL or Xv ?


    • #3
      Hi Bridgman; thanks for the quick reply As far as I have noticed, this only concerns OpenGL, XV seems to work fine. Activating vsync leads to an error about interrupts not working if enabling wait-for-interrupt in driconfig and a warning otherewise and, after some seconds, corruption and VERY slow rendering in glxgears (<1FPS) with all waiting methods.

      P.S.: Found it, the exact error is
      do_wait: drmWaitVBlank returned -1, IRQs don't seem to be working correctly.
      Last edited by DirtyHairy; 02-27-2009, 02:09 PM.


      • #4
        Just for the record: after discovering that I also get ugly artifacts and screen corruption (blackened window derorations etc.) after exiting a full screen OpenGL application (xscreensaver!) which only vanish after repeatedly switching workspaces, I have run some more tests with the opensource driver.

        Using the dynamic clocks option gives me values for power consumption that are nearly comparable to the good old times when powerplay was working, so I decided to live with the glitches still present in the radeon driver kick out the blob.

        To conclude this with a small rant: I must say that quality and speed of the blob have significantly increased over the last year. However, I also must say that I have not encountered a single release that had all features I am interested working satisfactorily: Xv, 2D, modest 3D, powersaving, vsync, stability (I don't care about compositing). Especially Xv has been a mess over a full year now and has just reached a working state for me now with the last few releases which are borked in other ways. I think the driver badly needs a stable fork which can actually be used on non-bleeding edge hardware without having to workaround around one or another issue. It really feels like being part of an endless beta testing program with no release drawing near at any point in the foreseeable future.

        I also have had my share of problems with the opensource driver (also speaking of my powermac which has R300 hardware) and can't confirm the often expressed sentiment that it "works just well on pre-R500", but going through subsequent revisions, you do get the impression that bugs are actually squashed and don't get just replaced with new ones.