Linux kernel does not support the SiS 5591/5592 AGP port?

[Bazango]

The Linux kernel does not support the SiS 5591/5592 AGP port? What does this mean?

I recently upgraded to an ATI 9000 Pro video card and an ASUS P4S533 motherboard. I was having no end of problems trying to get the video functioning properly. I could only get the basic "vesa" driver working and no dual display functionality at all. The Linux drivers supplied by ATI did not work.

Finally after trying a few kernels, I found some information in the kernel configuration using "make menuconfig" and "make xconfig" saying that the SiS 5591/5592 AGP chipset was not supported by Linux:

/dev/agpgart (AGP Support) (AGP)

AGP (Accelerated Graphics Port) is a bus system mainly used to
connect graphics cards to the rest of the system.

If you have an AGP system and you say Y here, it will be possible to
use the AGP features of your 3D rendering video card. This code acts
as a sort of "AGP driver" for the motherboard's chipset.

If you need more texture memory than you can get with the AGP GART
(theoretically up to 256 MB, but in practice usually 64 or 128 MB
due to kernel allocation issues), you could use PCI accesses
and have up to a couple gigs of texture space.

Note that this is the only means to have XFree4/GLX use
write-combining with MTRR support on the AGP bus. Without it, OpenGL
direct rendering will be a lot slower but still faster than PIO.

You should say Y here if you use XFree86 3.3.6 or 4.x and want to
use GLX or DRI. If unsure, say N.

This driver is available as a module. If you want to compile it as
a module, say M here and read <file:Documentation/modules.txt>. The
module will be called agpgart.

SiS chipset support (AGP_SIS)

This option gives you AGP support for the GLX component of
XFree86 4.x on Silicon Integrated Systems [SiS] chipsets.

Note that 5591/5592 AGP chipsets are NOT supported.

You should say Y here if you use XFree86 3.3.6 or 4.x and want to
use GLX or DRI. If unsure, say N.

I am not any kind of real authority on the subject of chipsets. All I am doing is interpreting the information provided me by my operating system and the kernel configurations. This is what I see when I use my KDE Control Center application:

Under Information and under that, PCI Information,

00:01.0 PCI bridge Silicon Integrated Systems [SIS] 5591/5592 AGP (prog-if 00 [Normal decode])
Flags: bus master, fast devsel, latency 0
Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
I/O behind bridge: 0000d000dfff
Memory behind bridge: e7000000-e7ffffff
Prefetchable memory behind bridge: f0000000-febfffff

Under XP Pro, the device at that same 00:01.0 location is called the "SIS Processor to AGP Controller". The location is refered to as "bus 0, device 1, function 0".

If the Linux kernel does not support my "Processor to AGP Controller", could this be the source of my problems with my ATI 9000 Pro video card? Would I be having the same problems with any AGP slot video card?

(Does this thread really belong in the Motherboards forum?)

[Sterling_Aug]

What part of NO don't you understand?

If it is not supported then there are no drivers available for that hardware. You either have to run VESA mode, downgrade to an older video card that is suppported, or load Windows on the system.

[Bazango]

If it is not supported then there are no drivers available for that hardware. You either have to run VESA mode, downgrade to an older video card that is suppported, or load Windows on the system.

This isn't about a video card, it is about the AGP port on the motherboard, isn't it? Explain.

[Nukes]

Right, I have a K7S5A, which uses the 5591 chip (actually its all on the 735 chip, but no matter, its still the one you're talking about)
I also have a radeon running with full AGP 4x and DRI support. Just compile the module, it works fine.
However, if you are using XF4.3 you will need to replace this module with the one from gatos.sf.net anyway as there is a version conflict between XFree86 4.3 and the agp/dri modules provided with the current stable (2.4) kernel.

So, to answer your question: The problems related to your video are driver related, but this chip works fine with linux. ATI also has Linux drivers out for this card I think, so look there.
I have written a howto on this subject as so many people seem to have trouble with it, but use it at your own risk as it is a slightly different card to the one I used.
http://www23.brinkster.com/nukes031/radeon.html

[Bazango]

Thanks, that's a pretty good clue.

I will inquire further. Maybe at this point I can make better sense of the instructions provided by ATI which are ... bad. Do I understand correctly that just because the kernel does not support my 5591/5592 AGP controller doesn't mean that support is not available?

Perhaps you could explain an observation made to me that the "5591/5592 AGP chipset" is a misnomer, that 5591/5592 refers to a Socket 7 motherboard main chipset.

[Nukes]

That would make sense actually. Here's what I get from dmesg |grep agp
Linux agpgart interface v0.99 (c) Jeff Hartmann
agpgart: Maximum main memory to use for agp memory: 439M
agpgart: Detected SiS 735 chipset
agpgart: AGP aperture is 64M @ 0xd0000000

I see it detected the 735, which would make sense with your idea. I am using the 735 chipset (AMD counterpart for yours) and it is working fine, 3d games run great. I have even tryed manually filling the hardware buffer with a 64mb image (I only have 32mb vram) and it worked fine.
SO, all I really know is that that controller works. That's the one integrated into the 735, and thats what I use without trouble. You explaination fits it quite well, as I remember having some trouble with a soyo super 7 board with the AGPgart. Cheers for clearing that up.

[Bazango]

Actually, I wasn't offering an explanation. I am still confused. Why does this information show up describing my AGP port as SIS 5591/5592 when my chipset is 645DX? Is that, or is that not correct and is this what the kernel configuration notes are refering to when they say the 5591/5592 AGP chipset is not supported?