only 64 out of 128 MB video RAM memory used - why?

[Michel Dänzer]

On Mon, 2009-01-05 at 16:04 -0500, Alex Deucher wrote: 
> On Mon, Jan 5, 2009 at 3:55 PM, Tomasz Chmielewski <mangoo at wpkg.org> 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.

Right, but FWIW it should be easy to make the driver use it for the
legacy 3D driver texture area for someone so inclined.


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer