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Maximum virtual size, radeonhd

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  • Maximum virtual size, radeonhd

    Here I read the following:
    Note that the maximum supported size of the virtual desktop for the Intel 945GM series of chipset with 3D acceleration enabled, is 2048x2048. The virtual screen can be larger but DRI will be disabled.
    Now I wonder: how big can the virtual screen size be when using radeonhd (or xf86-video-radeonhd) without losing DRI? Or isn't it a driver limitation, but rather a limitation of the grapich card?

    Edit: Woops. I wonder if DRI is available at all in radeonhd..

  • #2
    It's both card- and driver-dependant; the card puts the max bar in, and the driver can support that or something less. R500 class cards have 4096x4096 3d.


    • #3
      Thanks. Is this documentated somewhere?


      • #4
        It's mentioned on page 7 of the 5xx acceleration guide v1.3. The change actually happened between 3xx and 4xx (at least that's what the doc says ).

        DRI is fully supported in radeonhd since release 1.2.2, at least for GPUs up to 5xx and 690. Earlier versions (before 1.2.2) had support for DRI but the 2D acceleration paths could not use drm, so you could not have 2D and 3D acceleration at the same time.

        DRI support for 6xx and 7xx is in the "6xx-7xx-support" development branch. You also need the corresponding 6xx-7xx-support branch of drm. We don't have working mesa support for 6xx/7xx but that is getting closer; we're drawing triangles in house and might get glxgears running next week.
        Last edited by bridgman; 02-15-2009, 03:39 PM.


        • #5
          I see. Thank you (again)!


          • #6

            You're free to tell the driver whatever virtual you like. My code does the right thing and clamps down to the limits possible (another area in which it is quite unique). With 2d acceleration enabled, the limits are 4095x4095 if memory serves.


            • #7
              Depending on hardware/driver you may be limited to 2560x2560 resolution, see freedesktop bug 14099