AGP 2x

[markdog12]

I type in the command:

cat /proc/driver/nvidia/agp/status

and get an AGP rate of only 2x. I have a Geforce 2mx and it should have an AGP rate of 4x. I think this just might be a mistake because if it was running at 2x, the performance would be worse. But i want to make sure i'm getting the best performance possible. I have AGP set at 4x in the BIOS. Does anyone else get this result?

[chatins]

I just checked it on my nvidia tnt2 agp and in indicates agpgart is 2x. Since "nvidia" is the universal driver for this series of cards, that includes the gf2, it defaults to the lowest common denominator. You should be able to recompile the kernel module from src for better performance.

[mdwatts]

Add

options nvidia NVreg_ReqAGPRate=4

to /etc/modules.conf

Use NVdriver instead of nvidia if you are using the Nvidia drivers previous to version 4191.

[markdog12]

I'll give that a shot when i get home mdwatts, thanks

[markdog12]

i tried what you said MDWatts and rebooted. X wouldn't load when i rebooted however. The nvidia kernel wouldn't load. Another interesting thing is kudzu came up and said it was going to remove the printer. I said do nothing, i fixed the /etc/modules.conf file and rebooted. Do u know why it wouldn't take that line in the /etc/modules.conf file?

[JohnT]

If you failed to install the nvidia drivers before configuration, this could be a factor.

[markdog12]

my nvidia drivers work before i changed my /etc/modules.conf file

[mdwatts]

Try something like

pre-install nvidia modprobe "-k" "agpgart"
alias char-major-10-175 agpgart
alias char-major-195 nvidia
options nvidia NVreg_ReqAGPRate=4

BTW... options nvidia NVreg_ReqAGPRate=4 is from the Nvidia readme.

[markdog12]

i entered what you said in the /etc/modules.conf file and X loaded fine but it stills says the AGP rate is 2x. Here is my /etc/modules.conf file:

alias parport_lowlevel parport_pc
alias eth0 ne2k-pci
alias usb-controller usb-uhci
alias char-major-195 nvidia
options ide-cd dma=1
alias sound-slot-0 emu10k1
post-install sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -L >/dev/null 2>&1 || :
pre-remove sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -S >/dev/null 2>&1 || :
pre-install nvidia modprobe "-k" "agpgart"
alias char-major-10-175 agpgart
alias char-major-195 nvidia
options nvidia NVreg_ReqAGPRate=4

[mdwatts]

Try adding

Option "AGPMode" "4"

to the Device section of your X config.

[fishhead]

You should be aware that on some motherboards, AGP is "supposed" to go at 4x, however, because of problems with the hardware, it is unstable at anything greater then 2x. What kind of motherboard is it?

[markdog12]

I added that line to my XF86Config file, rebooted, but it still says my AGP rate is 2x

[markdog12]

AGP 4x works fine in Windows, so i don't think it's the motherboard.

[JohnT]

http://www.evil3d.net/articles/linux/nv95v96_2/

[bwkaz]

OK, guys, BACK UP! ;)

What are the contents of /proc/driver/nvidia/agp/card and /proc/driver/nvidia/agp/host-bridge? My guess is that one of those has an AGP rate of 2.

Is this a Via motherboard?

[JohnT]

Originally posted by bwkaz
OK, guys, BACK UP! ;)

What are the contents of /proc/driver/nvidia/agp/card and /proc/driver/nvidia/agp/host-bridge? My guess is that one of those has an AGP rate of 2.

Is this a Via motherboard?

If a Via, your out of luck.

[bwkaz]

Not really, but you do have to do a bit of dinking around:

$ cat /proc/driver/nvidia/agp/host-bridge
Host Bridge: Via Apollo Pro KT266
Fast Writes: Supported
SBA: Supported
AGP Rates: 4x 2x 1x
Registers: 0x1f000217:0x00000314
[bilbo@beta bilbo]$ cat /proc/driver/nvidia/agp/status
Status: Enabled
Driver: AGPGART
AGP Rate: [b]4x
Fast Writes: Enabled
SBA: Enabled I had to set a variable in os-registry.c in order to get this, though.

[JohnT]

I had to set a variable in os-registry.c in order to get this, though.

See my link, couple post above.

[bwkaz]

Originally posted by JohnT
See my link, couple post above. Yeah, but that link is for driver 0.9-6 (or so), not 1.0-4191 or 1.0-3123. It's old, in other words. ;)

I'm not sure, but I don't think SkipBiosPost is even a valid option anymore. The variable I changed was NVreg_EnableVia4x.

[JohnT]

It's the method, not the madness.:D

[markdog12]

[mark@u87n29 driver]$ cat /proc//driver/nvidia/agp/status
Status: Enabled
Driver: AGPGART
AGP Rate: 2x
Fast Writes: Disabled
SBA: Disabled
[mark@u87n29 driver]$ cat /proc/driver/nvidia/agp/card
Fast Writes: Supported
SBA: Not Supported
AGP Rates: 4x 2x 1x
Registers: 0x1f000017:0x1f000102
[mark@u87n29 driver]$ cat /proc/driver/nvidia/agp/host-bridge
Host Bridge: Via Apollo Pro KT133
Fast Writes: Not Supported
SBA: Supported
AGP Rates: 2x 1x
Registers: 0x1f000203:0x00000102
[mark@u87n29 driver]$

[markdog12]

I searched for the file to edit with:

[root@u87n29 driver]# find / -name 'os-registry.c' -print
[root@u87n29 driver]#

Do u know what i have to have installed to have this file?

[mdwatts]

The binary rpm packages will not include 'os-registry.c' as you will need to use the source tarballs instead.

Download the source, extract, locate 'os-registry.c', make the modifications and then compile as per the instructions.

[bwkaz]

Yep. And make sure in your BIOS that you have 4x selected. It may be that the host-bridge file is only reporting 2x because the driver won't enable 4x on a Via chipset, or it may be reporting 2x because that's all that the BIOS reports that it can handle.