Bug#484583: xserver-xorg-video-nv: Failed to set up write-combining range

[Ryo Furue <furue@hawaii.edu>]

Hi Brice,

Thank you for your response.

| > Package: xserver-xorg-video-nv
| > Version: 1:2.1.9-1
| > Severity: normal
| >
| > I have this warning in my /var/log/Xorg.0.log :
| >
| >   (WW) NV(0): Failed to set up write-combining range (0xd8000000,0x8000000)
| >
| > and this in /var/log/kern.log
| >
| >    kernel: mtrr: type mismatch for d8000000,8000000 old: write-back new: write-combining
| >   
| 
| Not sure this is actually a bug. The kernel is mainly responsible for
| marking ranges as WC. But sometimes there are too many entries allocated
| so Xorg cannot get a new one. And sometimes, the existing ranges are
| difficult to modify to satisfy what Xorg wants.
| 
| What does /proc/mtrr contains before and after starting X?

I've just found a chance to restart my machine.  I don't know an
easy way of getting a status "before X", so I shut down the machine
and booted to a single-user mode, where I copied the contents of
/proc/mtrr to another file.  I then exited, which brought the machine
to the regular mode.  I logged in from KDM to my regular session, and
copied the contents of /proc/mtrr again.

The result is that /proc/mtrr didn't change between before and after X
and is

  reg00: base=0x00000000 (   0MB), size=65536MB: write-back, count=1
  reg01: base=0xcff00000 (3327MB), size=   1MB: uncachable, count=1
  reg02: base=0xd0000000 (3328MB), size= 256MB: uncachable, count=1
  reg03: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1
  reg04: base=0xff0000000 (65280MB), size= 256MB: uncachable, count=1

Does this info help?

Regards,
Ryo