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  • kadambi
    started a topic Memory on graphics card

    Memory on graphics card

    I looked around for this problem and couldn't find any solutions. On my X800 Fedora 9 (radeon 6.8.0) box, I see this message

    (II) RADEON(0): Detected total video RAM=262144K, accessible=262144K (PCI BAR=262144K)
    (--) RADEON(0): Mapped VideoRAM: 262144 kByte (256 bit DDR SDRAM)


    Fair enough. It is a 256 MB PCIE card.

    However on the Fedora 10 X1650 AGP card, the mapped memory seems half:

    (II) RADEON(0): Detected total video RAM=524288K, accessible=262144K (PCI BAR=262144K)
    (--) RADEON(0): Mapped VideoRAM: 262144 kByte (128 bit DDR SDRAM)

    I see the same on my FreeBSD 6.3 system with ATI 9250 256 MB AGP card which showed the mapped videoRAM to be 128 MB. I replaced the card with ATI 9550 AGP 256MB card and it showed the right mapped videoRAM (256 MB).

    After some google search, I came across several posts mentioning that it is PCI_BAR that is setting the range and the actual memory is still 512MB and not half.

    So, I uploaded 4 512x512x64 RGBA textures into the ATI X1650 512MB card (on the Fedora 10 system). 4 such textures take 256 MB memory and a 512MB card should be able to handle it.

    But I got a "driallocatetexture 636", which means there isn't enough memory, which led me to suspect that the driver is seeing only 256MB memory. Right?

    Any ideas?

  • marek
    replied
    Originally posted by nanonyme View Post
    Slower than reading from hard disk?
    Maybe on AGP.

    Leave a comment:


  • kadambi
    replied
    Originally posted by devius View Post
    Nice to see that after 2 years your problem is solved So, this has been a problem ever since Fedora 10 up to now?
    Well, this was a new feature essentially. Without KMS and memory manager, you can't address beyond PCI BAR address (256MB). With memory manager now in place, it works fine.

    Leave a comment:


  • nanonyme
    replied
    Originally posted by agd5f View Post
    Reading from vram with the CPU is REALLY slow.
    Slower than reading from hard disk?

    Leave a comment:


  • devius
    replied
    Originally posted by kadambi View Post
    It works!! I tested it on F14 alpha and it works great.
    Nice to see that after 2 years your problem is solved So, this has been a problem ever since Fedora 10 up to now?

    Leave a comment:


  • kadambi
    replied
    It works!! I tested it on F14 alpha and it works great.

    dmesg confirms the full memory usage:

    radeon 0000:01:00.0: VRAM: 512M 0x00000000 - 0x1FFFFFFF (512M used)
    [drm] Detected VRAM RAM=512M, BAR=256M
    [drm] radeon: 512M of VRAM memory ready
    [drm] vram apper at 0xD0000000

    Leave a comment:


  • bridgman
    replied
    I wouldn't want to swap to VRAM on a card I was also using for graphics - in addition to the issues related to sharing VRAM you would also be sharing BAR address space, which might be an even bigger problem.

    I guess swapping to an unused graphics card would still be OK but not sure whether the driver would set things up properly if there was no display attached.

    Leave a comment:


  • agd5f
    replied
    Also, you can never have enough vram. LOTS of pixamps get stored in vram (especially when running a compositor), so you are probably using more than you think.

    Leave a comment:


  • agd5f
    replied
    Reading from vram with the CPU is REALLY slow.

    Leave a comment:


  • curaga
    replied
    Or if the card has something way overkill, like anything above 512mb, why would it be a bad idea to use it for swap?

    (ref overkill for my uses, my display is 1600x900)

    Leave a comment:

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