# AGP Fast writes wont enable! Help

## MaDDeePee

Hi ppls,

i got stuck with my Nvidia 6600GT Gentoo Box!

Please look @ the bottom of my dmesg:

 *Quote:*   

> maddeepee@MaDWorkStatioN ~ $ dmesg
> 
> Linux version 2.6.14-gentoo-r2 (root@MaDWorkStatioN) (gcc-Version 3.3.6 (Gentoo 3.3.6, ssp-3.3.6-1.0, pie-8.7.) #11 SMP PREEMPT Sat Nov 19 20:12:19 CET 2005
> 
> BIOS-provided physical RAM map:
> ...

 

looks like Nvagp should work, right?   :Very Happy: 

This also should be fine:

 *Quote:*   

> maddeepee@MaDWorkStatioN ~ $ cat /proc/driver/nvidia/agp/card
> 
> Fast Writes:     Supported
> 
> SBA:             Supported
> ...

 

...and this does me headache:

 *Quote:*   

> maddeepee@MaDWorkStatioN ~ $ cat /proc/driver/nvidia/agp/status
> 
> Status:          Enabled
> 
> Driver:          NVIDIA
> ...

 

What to do to enable this FAST WRITE option?

Also done:

 *Quote:*   

> 
> 
> maddeepee@MaDWorkStatioN ~ $ cat /etc/modules.d/nvidia
> 
> # Nvidia drivers support
> ...

 

any hints there?

Regards,

Daniel   :Very Happy: 

Btw: Sry, i hate this long copy/paste threads too   :Very Happy: 

----------

## banjaxb

Does your BIOS have a setting to turn Fast Writes off?  That is often set to off with default settings.

Have a look in your /etc/modules.conf file.  See if it got updated with this:

```
#

# To enable both for instance, uncomment following line:

#

options nvidia NVreg_EnableAGPSBA=1 NVreg_EnableAGPFW=1
```

If those are both okay, could you post the device section of your xorg.conf?

Cheers,

banjaxb

----------

## Headrush

Are you sure your motherboard supports fast writes? not all do.

What is output of

```
cat /proc/driver/nvidia/agp/host-bridge
```

----------

## nirax

hi,

ive got exactly the same problem:

nvidia 6800gt, shuttle sn41g2 (nforce2) XPC

fastwrites support in bios is on

```

dinu ~ # cat /proc/driver/nvidia/agp/status

Status:          Enabled

Driver:          NVIDIA

AGP Rate:        8x

Fast Writes:     Disabled

SBA:             Enabled

```

```

dinu ~ # cat /proc/driver/nvidia/agp/card

Fast Writes:     Supported

SBA:             Supported

AGP Rates:       8x 4x

Registers:       0xff000e1b:0x1f004302

```

```

Host Bridge:     PCI device 10de:01e0

Fast Writes:     Supported

SBA:             Supported

AGP Rates:       8x 4x

Registers:       0x1f00421b:0x00000302

```

```

Section "Device"

        Identifier "gf68"

        Screen 0

        Driver "nvidia"

        BusID "PCI:2:0:0"

        Option "NvAGP" "1"

        Option "Coolbits" "1"

        Option "RenderAccel" "true"

        Option "CursorShadow" "true"

        Option "CursorShadowAlpha" "64"

        Option "AllowGLXWithComposite" "true"

Endsection

```

/etc/modules.conf: (nvidia part)

```

..

### modules-update: start processing /etc/modules.d/nvidia

# Nvidia drivers support

alias char-major-195 nvidia

alias /dev/nvidiactl char-major-195

options nvidia NVreg_EnableAGPSBA=1 NVreg_EnableAGPFW=1

..

```

any ideas?

greetings,

nirax

----------

## MaDDeePee

 *Headrush wrote:*   

> Are you sure your motherboard supports fast writes? not all do.
> 
> What is output of
> 
> ```
> ...

 

All is set how it should be!   :Crying or Very sad: 

 *Quote:*   

> maddeepee@MaDWorkStatioN ~ $ cat /proc/driver/nvidia/agp/host-bridge
> 
> Host Bridge:     PCI device 8086:2578
> 
> Fast Writes:     Supported
> ...

 

xorg.conf:

 *Quote:*   

> 
> 
> Section "Device"
> 
>         BoardName    "Xfx Geforce 6600GT Ausgang #1"
> ...

 

----------

## j-m

Quite frankly, I'd say this is just a waste of time... The performance gain is not even measurable.

----------

## MaDDeePee

Taking a look at that you are a developer, i cant understand your answer...i would like to understand how this work, why it doesnt work and i also want to help others with this post...

----------

## j-m

 *MaDDeePee wrote:*   

> Taking a look at that you are a developer, i cant understand your answer...i would like to understand how this work, why it doesnt work and i also want to help others with this post...

 

You know, everyone has preferences. I prefer not to waste my time with things that are simply not worth it; fastwrite is one of those things. It gains you nothing except possibly instability under Windows and the same is valid for Linux. If you want do spend next couple of days/weeks trying to enable this feature, then read the docs that come with nVidia binary drivers and if you succeed, then enjoy the benefits which amount to one big zero.

----------

## nirax

actually some may have read docs and while it still does not work, can we concentrate now on making it work rather discussing why someone wants a feature to work or not

----------

## banjaxb

Try using the NVagp instead by setting

```
Option "NvAGP" "3"
```

 in the device section of your xorg.conf.  Restart X server and see if it makes any difference.

----------

## nirax

hi banjaxb,

thanks for your answer,

the 3rd option is trying AGPGART. this will AFAIK not work with nvidia-fastwrite-module configuration.

theres no different behavior (if it does not find agpgart it uses nvidia agp module on xorg startup), as i didnt compiled agpgart to the kernel.

greetings,

nirax

----------

## MaDDeePee

 *banjaxb wrote:*   

> Try using the NVagp instead by setting
> 
> ```
> Option "NvAGP" "3"
> ```
> ...

 

No, it doesnt...   :Mad: 

Anyways, AGPGard doesnt work right now with 2.6.14-r2 and im allways running Nvagp....

----------

## Headrush

 *nirax wrote:*   

> the 3rd option is trying AGPGART. this will AFAIK not work with nvidia-fastwrite-module configuration.

 

Sure it will. Working perfect on my system for over a year on multiple motherboards.

----------

## nirax

headrush,

this is very interesting. actually i was using AGPGART before with the same module setting and ran into the same problem (fastwrites were not on)

this was the original reason why i switched to nvidia agp.

thi was the thread: https://forums.gentoo.org/viewtopic-t-397264-highlight-nirax.html

greetings,

nirax

----------

## Headrush

nirax, I'm not sure how much fast writes would make a difference on modern AGP/PCI interfaces and new video cards anyways.

I'll do some test with and without fast writes and post the differences.

----------

## Headrush

I did a rudimentary test on my system with and without fast writes and the results are surprising.

Remember, these are simple tests and I ran them 5 times each to make sure results were consistent.

All tests are 32 bit at 1280x768 resolution. High settings in UT2004.

With Fast writes:

 glxgears: 7200 fps

 ut2004: 68fps 

Without Fast writes:

 glxgears: 7450 fps

 ut2004: 80 fps

Very interesting.

----------

## nirax

strange results indead.the last time i tested under windows it was some frame(s) difference in favor of fastwrites.

do you get the same effect using NVIDIA AGP ?

greetings,

nirax

----------

## Headrush

 *nirax wrote:*   

> strange results indead.the last time i tested under windows it was some frame(s) difference in favor of fastwrites.
> 
> do you get the same effect using NVIDIA AGP ?
> 
> greetings,
> ...

 

The nvidia agp doesn't support my chipset .

----------

