Bug#493521: xserver-xorg: can only use half of my video RAM
On Wed, 2008-09-17 at 08:53 -0700, Zack Weinberg wrote:
> On Tue, Sep 16, 2008 at 9:56 PM, Brice Goglin <Brice.Goglin@ens-lyon.org> wrote:
> > Zack Weinberg wrote:
> >> (II) RADEON(0): Generation 2 PCI interface, using max accessible memory
> >> (II) RADEON(0): Detected total video RAM=524288K, accessible=262144K
> >> (PCI BAR=262144K)
> >> (--) RADEON(0): Mapped VideoRAM: 262144 kByte (256 bit DDR SDRAM)
> >>
> >
> > I am reading this as:
> > * the driver rea somewhere in the registers that the board has 512MB
> > * the PCI config space only makes 256 available through I/O MEM
> >
> > It could mean that the board keeps 256MB available for its own use
> > (internal memory management, or DMA from/to the host) but the host
> > cannot write/read directly in there.
>
> Yeah, that's how I read it too. It might be harmless; I'm really only
> concerned with it because I wonder if it's a cause of some of the
> other problems (like maybe the screen flicker issues would go away if
> the X server wasn't having to do something unusually slow with the
> frame buffer -- I guess a 3520x1200x32 fb is only 128MB or so, but
> still)
3520 * 1200 * 4 / 1024 / 1024 = 16.1133 MB (the log file should mention
this and other sizes)
The above is harmless other than leaving part of video RAM unused.
> The "Cannot get VRAM scratch space" part is more of a worry, honestly;
> that seems like it might mess up things the firmware is doing.
No, I think it's normal and harmless.
As Alex pointed out, the flicker is likely due to the two display
controllers and the accelerator fighting for memory bandwidth. You could
try playing with Option "DisplayPriority".
--
Earthling Michel Dänzer | http://tungstengraphics.com
Libre software enthusiast | Debian, X and DRI developer
Reply to: