On Mon, Jan 5, 2009 at 3:55 PM, Tomasz Chmielewski <[email protected]> wrote:
> I have a Radeon 9200 PCI video card.
>
> I noticed only 64 MB out of 128 MB of video RAM memory is used:
>
> (II) RADEON(0): Generation 2 PCI interface, using max accessible memory
> (II) RADEON(0): Detected total video RAM=131072K, accessible=65536K (PCI 
> BAR=65536K)
> (--) RADEON(0): Mapped VideoRAM: 65536 kByte (64 bit DDR SDRAM)
>
> Why is it so?
>

The PCI BAR size is only 64 MB so that's the most we can access.  The
GPU can access the rest; it's just the CPU that's limited to 64 MB.
Unfortunately, we need proper memory management to handle the non-CPU
addressable vram for things like software access.  Work has begun on
adding proper memory management to the drm, so it will be supported
eventually.

>
> The system has also AGP card with 256 MB memory, and full 256 MB is used 
> there.

On that card the PCI BAR is 256 MB so the CPU can access the full
amount of vram.

Alex
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