Need help with mtrr & agpgart

Need help with mtrr & agpgart

[Ochal Christophe]

I've been doing a little digging in my system since i was unable to get
DRI running on my current motherboard (see my prior posts regarding a
possible bug in agpgart), and i noticed that i don't get any lines
in /proc/mtrr expect for my main memory.

The entry seems correct, the size specified is also correct, however, i
don't get any write-combining lines.

This is what i get:

eg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1

This is what i should get:
eg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1
reg01: base=0xd0000000 (3328MB), size= 128MB: write-combining, count=1
reg02: base=0xf0000000 (3840MB), size= 128MB: write-combining, count=1

The required modules are loaded (agpgart & amd64-agp), but as previously
reported, amd64-agp is unable to read the proper aperture size.

As far as i've come to understand, these issue's are most likely
related, and quite possibly related to the motherboard BIOS, so i'm
wondering about any work-arrounds for this.

Cheers all

Re: Need help with mtrr & agpgart

[Kurt Wall]

On Mon, Jan 02, 2006 at 01:52:01AM +0100, Ochal Christophe took 0 lines to write:
> I've been doing a little digging in my system since i was unable to get
> DRI running on my current motherboard (see my prior posts regarding a
> possible bug in agpgart), and i noticed that i don't get any lines
> in /proc/mtrr expect for my main memory.
> 
> The entry seems correct, the size specified is also correct, however, i
> don't get any write-combining lines.
> 
> This is what i get:
> 
> eg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1
> 
> This is what i should get:
> eg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1
> reg01: base=0xd0000000 (3328MB), size= 128MB: write-combining, count=1
> reg02: base=0xf0000000 (3840MB), size= 128MB: write-combining, count=1

I don't get much better on my AMD64 system:

$ cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size= 512MB: write-back, count=1
reg01: base=0x1ff00000 ( 511MB), size=   1MB: uncachable, count=1

Kurt
-- 
Be braver -- you can't cross a chasm in two small jumps.

Re: Need help with mtrr & agpgart

[Ochal Christophe]

On Sun, 2006-01-01 at 20:14 -0500, Kurt Wall wrote:
> On Mon, Jan 02, 2006 at 01:52:01AM +0100, Ochal Christophe took 0 lines to write:
> > I've been doing a little digging in my system since i was unable to get
> > DRI running on my current motherboard (see my prior posts regarding a
> > possible bug in agpgart), and i noticed that i don't get any lines
> > in /proc/mtrr expect for my main memory.
> > 
> > The entry seems correct, the size specified is also correct, however, i
> > don't get any write-combining lines.
> > 
> > This is what i get:
> > 
> > eg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1
> > 
> > This is what i should get:
> > eg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1
> > reg01: base=0xd0000000 (3328MB), size= 128MB: write-combining, count=1
> > reg02: base=0xf0000000 (3840MB), size= 128MB: write-combining, count=1
> 
> I don't get much better on my AMD64 system:
> 
> $ cat /proc/mtrr
> reg00: base=0x00000000 (   0MB), size= 512MB: write-back, count=1
> reg01: base=0x1ff00000 ( 511MB), size=   1MB: uncachable, count=1

I did some more tests, i replaced my Radeon card with an older R128 one,
and enabling DRI makes it crawl, it's worse then windows95 on a 386 :(

It seems there's an incompability with my hardware somewhere, but i
can't put my finger to the exact cause of the system, the only known
recurrence is that agpgart incorrectly specifies the agp aperture size
regardless of AGP card i use, and regardless of my BIOS settings.

With this R128 i *can* enable DRI, but it only sees 8MB of video ram,
the mtrr entry has a write-combining line of 32MB (the incorrect size of
my AGP aperture) and any disk access seems to halt the X server.

I've never had any problem like this before with linux, and i'm stumped
as to how to solve it, hopefully, someone here can provide me with some
more hints & tricks