AGP and fast writes anyone?

[brblueser]

Hi there,

I just can't seem to be able to enable fast writes on my Linux system. Both mobo and graphics card support it, and it actually works with Win2k on the same machine.

I have tried passing module parameters:

~ grep nvidia /etc/modules.conf
options nvidia NVreg_EnableAGPFW=1 NVreg_EnableAGPSBA=1

and I have even tried modifying os-registry.c by hand, as suggested on this thread (http://www.nvnews.net/vbulletin/showthread.php?s=&threadid=4258), but either way results are the same:

~ cat /proc/driver/nvidia/agp/status
Status: Enabled
Driver: NVIDIA
AGP Rate: 4x
Fast Writes: Disabled
SBA: Disabled

Am I forgetting something?

I am using latest drivers (4191) and XFree 4.2.1 on a 2.4.20 kernel, and my graphics card is a GeForce2 MX 400.

TIA

[mtrr]

mobo make and model ?

cheers

[brblueser]

Sorry, I assumed that the fact that it works for Win2k on the same computer would suffice. My bad.

My mobo is a MSI K7T266 Pro2 (http://www.msi.com.tw/program/products/mainboard/mbd/pro_mbd_detail.php?UID=28&MODEL=MS-6380), and my GF2 is made by EGO force. Graphics card's manual says it supports fast writes, and it seems to work fine on Win2k (SiSoft Sandra reports fast writes are supported and enabled, and I have been able to play games without a probl). BIOS has a specific option for fast writes, and it is on.

Please let me know if you need additional info.

Thks.

[bwkaz]

As I said in the PM, what do /proc/driver/nvidia/agp/card and /proc/driver/nvidia/agp/host-bridge contain?

Don't bother responding to my PM anymore, just post the files here.

[brblueser]

Hi bwkaz,

sorry, I read this too late and had sent you a PM already. Just ignore it.

The info you requested is:

~ cat /proc/driver/nvidia/agp/card
Fast Writes: Not Supported
SBA: Not Supported
AGP Rates: 4x 2x 1x
Registers: 0x1f000007:0x1f000104

~ cat /proc/driver/nvidia/agp/host-bridge
Host Bridge: Via Apollo Pro KT266
Fast Writes: Supported
SBA: Supported
AGP Rates: 4x 2x 1x
Registers: 0x1f000217:0x00000104

BIOS support for fast writes is enabled, and the driver seems to be detecting it right. As for the card, I believe it is an "el cheapo" card ("EGO force", I could never find the manufacturer's site on the net)... anyway, its manual says it supports fast writes, and this seems to be working with Win2k (SiSoft Sandra reports fast writes are enabled, but it could be host-bridge info only; I will double check it in a couple of mins).

Could it be that the driver is misdetecting the card's capabilities? Can I force it to bypass detection and try to use fast writes anyway? (actually this is what I thought I was doing with those module params)

[bwkaz]

Originally posted by brblueser
~ cat /proc/driver/nvidia/agp/card
Fast Writes: Not Supported
SBA: Not Supported
AGP Rates: 4x 2x 1x
Registers: 0x1f000007:0x1f000104 The card is reporting to the kernel driver that neither fast writes nor sidebanding are supported.

Are you using nVidia's reference drivers in Win2K, or the drivers that came with the card? If you're using the drivers that came with the card, then it's possible that that card requires something special to enable FW/etc., and the manufacturer is the only person that knows how to enable it. Might be worth uninstalling those and installing nVidia's 2K reference drivers, then seeing what Sandra says.

The driver isn't mis-detecting it, unless (like above) the card is non-standard. The information in /proc is directly from the kernel, which gets it directly from what the card is reporting...

You can't force anything to be enabled if it isn't present. ;) What you were doing with the module parameters (or the edit of os-registry.c, if you did that) was only enabling them, not forcing them on. They're both ("they" being SBA and FW) disabled all the time by default because of stability issues with some combinations of hardware, but they can only be enabled when both components (card and host bridge) report supporting them.

Not really any answers... :-/

[brblueser]

Originally posted by bwkaz
Are you using nVidia's reference drivers in Win2K, or the drivers that came with the card? [...] Might be worth uninstalling those and installing nVidia's 2K reference drivers, then seeing what Sandra says.

I am using latest official NVidia drivers (40.72). This is what I get from Sandra:

Mainboard information -> AGP Bus -> Fast-Writes enabled -> Yes
PCI,AGP Info -> AGP Capabilities -> FW Transfers support -> Yes

Now, this raises the question: could these be related to the host-bridge info, and not to the card info? I mean: they would mean only "yes, mobo supports FWs"? I couldn't find any specific Sandra module that would certify FWs are indeed being used. Anyone knows of any such module (or any other tool whatsoever)?

The driver isn't mis-detecting it, unless (like above) the card is non-standard. The information in /proc is directly from the kernel, which gets it directly from what the card is reporting...

Well, I wouldn't bet much on this card... as I said, it's manufacturer doesn't even have a web page. So, chances it is not really standard aren't negligible... I have been considering upgrading to a GF4 for a while, I was just waiting for prices to get a little lower (Christmas time is not necessarily the best time to buy things ;)). However, in the meantime I will have to stick to my good old "el cheapo" GF2... =T

You can't force anything to be enabled if it isn't present. ;) What you were doing with the module parameters (or the edit of os-registry.c, if you did that) was only enabling them, not forcing them on. They're both ("they" being SBA and FW) disabled all the time by default because of stability issues with some combinations of hardware, but they can only be enabled when both components (card and host bridge) report supporting them.

Not really any answers... :-/

Well, I appreciate you trying anyway :) At least I might become convinced I have to dump this card and go for a GF4...

The only thing I still want to do is to try to make sure FWs aren't being used for sure on Win2k -- because if they are, then there has to be a way to do it on Linux too.

Thank you very much for spending some time on this.