[Dri-users] Radeon: Video Ram not detected correctly

[Roland Scheidegger]

Jan Gukelberger wrote:
> Hi,
> 
> I've got a notebook with a Mobility Radeon 9000 graphics chip with 64 MB
> VRAM.
> However, most of the time, Xorg does only detect 32 MB, although there
> are some occassions (about one in 5-10 boots) when it correctly detects
> the whole RAM.
> 
> This is an Xorg.0.log diff extract between the two cases:
> 
> ------------------------------------------------------------------------
> -(II) RADEON(0): Detected total video RAM=32768K, accessible=65536K (PCI BAR=131072K)
> -(--) RADEON(0): Mapped VideoRAM: 32768 kByte (64 bit DDR SDRAM)
> +(II) RADEON(0): Detected total video RAM=65536K, accessible=65536K (PCI BAR=131072K)
> +(--) RADEON(0): Mapped VideoRAM: 65536 kByte (128 bit DDR SDRAM)
> ------------------------------------------------------------------------
> 
> Whole (failed) log and the complete diff attached.
> 
> I tried 
> 	Option "VideoRam" "65536"
> in my xorg.conf but this gets ignored.
> 
> I only recently started to notice this behaviour when I installed Compiz
> which fails to display maximized windows correctly (resolution
> 1440x1050) when only 32 MB are available.
> 
> Is there anything I could tweak or try? Any hints would be appreciated. 
> If you need more infos, config files, etc. feel free to ask.

This looks to me like it could be related to the power saving features
(powerplay). It is possible to disable one of the two memory channels of
the chip, and there is actually a comment in the driver code that
correct ram detection will fail if one of the channels is disabled. I'm
not sure why it would sometimes work and sometimes not though, it seems
a bit unlikely the bios would mess with that.
(cc to xorg as it's not really a dri-related problem)

Roland