Total lack of AGP accel

[Lemming]

No matter what I do, I can't seem to get Linux (several distros) to recognise the AGP on my KM4M-L motherboard. Well I'll rephrase that slightly, cards installed there will work, but only like PCI cards (i.e. v.slow) agpgart won't modprobe, and the Nvidia AGP driver (NvAgp) won't do it either.

I heard there's a work around (the mobo has a VIA chipset, I forget which one but I can look it up if needed) but couldn't find it when I was looking around on the net for it tonight.

[bwkaz]

Look up which chipset. :)

Depending on that, the workaround that I'm thinking of (that is, agp_try_unsupported=1 on the modprobe command line) might not even work.

[Lemming]

chipset is the KM400 chipset (would have said this last night but didn't have the manual to hand)

[hard candy]

You didn't say which distro or kernel, may have to recompile the kernel to support the agp module for that chipset, again it depends on the distro and kernel.

[bwkaz]

Yeah, try to /sbin/modprobe agpgart agp_try_unsupported=1 before starting X (with "NvAgp" set to "3" in your XF86Config), and see if that helps at all. That chipset is probably newer than your agpgart kernel module, so it's not specifically recognized as anything. But it should work just like any other Via AGP chipset.

If that works, add options agpgart agp_try_unsupported=1 to your /etc/modprobe.conf and run /sbin/depmod -ae as root, to make the option get applied every time the agpgart module gets loaded.

[Lemming]

tried, no joy, same error as before which I can't copy and paste cos the comp in question isn't currently on the net.

[bwkaz]

Copy the relevant parts of the log file(s) to a floppy maybe?

[Lemming]

No floppy drive on the computer in question, managed to get the wireless network to work (somehow) so I can now give errors. The error I get on attempting to probe agpgart is:

[root@localhost lemming]# /sbin/modprobe agpgart /lib/modules/2.4.20-8/kernel/drivers/char/agp/agpgart.o: init_module: No such device
Hint: insmod errors can be caused by incorrect module parameters, including invalid IO or IRQ parameters.
You may find more information in syslog or the output from dmesg
/lib/modules/2.4.20-8/kernel/drivers/char/agp/agpgart.o: insmod /lib/modules/2.4.20-8/kernel/drivers/char/agp/agpgart.o failed
/lib/modules/2.4.20-8/kernel/drivers/char/agp/agpgart.o: insmod agpgart failed

[bwkaz]

Is there any more info in the output of dmesg?

Usually that message comes from not actually having the hardware that the module is built to support in your machine. Are you sure the agpgart module was built with Via support? Well, this looks like a(n ancient) Red Hat kernel, so maybe it was. It might just not know about the PCI ID though... is there any way you can get a newer kernel?

[Lemming]

When doing the try unsupported thing I get:

agpgart: Trying generic Via routines for device id: 3205
agpgart: unable to determine aperture size.

and then the same as above.

EDIT: Yes it's a stock Redhat 9 kernel, I did it just now on Redhat, but a few distros have given me the same result such as Slackware and Knoppix (HD install)

[bwkaz]

I don't really know then. Unless either 2.4.23 or 2.6.0 have support for that device ID (3205, that is)...

[Gertrude]

Check your ".config" file for your kernel in /usr/src/linux/. Your kernel may not support the motherboard chipset fully. Look and see if you see this line.

# CONFIG_AGP_VIA is not set

If that is in there commented out you will have to recompile. Go to Character Devices enable 'agpgart' as a module. Then load the VIA chipset so its built into the kernel, and not as a module. Then take it from there.

I did this with Nforce2 chipset and a Radeon 9700 pro. It worked after I did that, and installed the Radeon drivers. Obviously I didn't add support for the VIA chipset. I had to add support for the NVIDIA one.

[Lemming]

2.6 seems to be ok with it, tried Fedora with a 2.6 kernel and it seems to have got detected ok.