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worong GPU Speed information?

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  • worong GPU Speed information?

    after changing from fglrx to xf86-video-ati on my HD 4670 Games like Nexuiz were jerking a bit. So I decided to overglock my GPU a bit.
    For that I used atiflash on a USB-Stick and RBE in a virtual machine. I changed everything from 750 to 800, saved the new BIOS on the USB-Stick, bootet from it and flashed.

    After that I had a look at /sys/kernel/debug/dri/0/radeon_pm_info but it is still showing me 750 mHz:
    default engine clock: 750000 kHz
    current engine clock: 749250 kHz
    default memory clock: 800000 kHz
    current memory clock: 796500 kHz
    voltage: 1250 mV
    PCIE lanes: 16
    The strange thing is that nexuiz isn't jerking anymore but I didn't change anything other than the BIOS.

    So my question is: Is the information from /sys/kernel/debug/dri/0/radeon_pm_info valid? Has anybody running a card with modified BIOS and can check this?

    P.S. Sorry for my bad english.

  • #2
    I tested some more and it seems like /sys/kernel/debug/dri/0/radeon_pm_info is showing the OverDrive (default?) settings. Is this a bug or a feature?
    And which speed is my card running now?
    And does this mean there is OverDrive support in the free driver? But if so, where are the userspace tools?
    Questions about questions, hopefully somebody knows the answers.


    • #3
      On my HD4850 it does the same (I don't have the card at hand right now, so I can't test it more). I also have it BIOS modified, but the driver only uses the "default" clocks.
      The BIOS for that card has several frequency profiles; boot, 2d, 3d, and uvd. I modified the "3d" clocks and both the Windows and fglrx drivers work fine. However, radeon does not seem to use the "3d" frequency profile and rather seems to default to the "boot" profile, even if I mess around with the driver's pm options. I never tried to change the "boot" clocks, so it may be possible that changing those may give you the desired effect.


      • #4
        I changed every clock from 750 to 800. So the boot clock should be at 800, too.
        Then I changed the default OverDrive clocks (which is hard as this can only be done by using clocks from another card with the same chip, as I read) and /sys/kernel/debug/dri/0/radeon_pm_info showed the new clocks from OverDrive. but that were wrong clocks (pushing the ram clock from 800 to 1000 but don't changing the GPU clock) so I changed it back to the default values of my card.

        So my questions still are:
        - Is /sys/kernel/debug/dri/0/radeon_pm_info showing the real clocks my card is running at?
        - Is the free driver supporting OverDrive? And if so: How can I increase my OverDrive clocks without touching the BIOS (this would be very nice) with the free driver?


        • #5
          Comeon guys, I thought AMD people are active in this forum, so if nobod can answer my questions here, who can?


          • #6
            Flashing/editing your vbios voids your warranty and we won't support it. It is enough work supporting all of the various cards out there today before having to deal with user customizations that may introduce all sorts of problems. The source is available if you want to play with it yourself; but I would suggest sticking with the original vbios.

            To elaborate, the vbios stores the card configuration:
            - number and type of connectors on the card
            - display encoder routing
            - i2c line mapping
            - type and timing of the vram used
            - thermal solution used
            - safe clock and voltage combinations for power management
            - etc.

            Changing any of these can cause loss of functionality (flashing your card with a vbios that has different connectors: DVI + displayport vs. DVI + VGA, etc.), or stability issues (different vram timing due to different vram vendors, unstable clock combinations).


            • #7
              Thanks for the hint but this still don't answer my questions.
              Let me rewrite them:
              - Where does /sys/kernel/debug/dri/0/radeon_pm_info read the infos from.
              - Is the free driver supporting OverDrive? And if so: How can I increase my OverDrive clocks without touching the BIOS (this would be very nice couse I don't have to flash my BIOS if so) with the free driver?
              - Is the card running on the OverDrive (default) speed, on the BIOS hardcoded speed or on a mix of this?

              So now the questions are more general and don't rely an a modded BIOS.