question about agpgart ?

xushi · 05-09-2005, 08:16 AM

Hi all,

I'm trying to find out what exactly is agpgart. I understand it gives advanced possibilities for systems that have AGP support. But the info in the kernel says

Quote:

This code acts as a sort of "AGP driver" for the motherboard's chipset.

Does that refer to the northbridge? Because i thought it refered to the graphics chipset itself, until i noticed it had options for Nforce (which i'm familiar with), along with other nbridges..

And, what if i have a chipset which isn't on the list? Does that mean agpgart won't work for me? Will it be safe for me then to completly disable it?

My bridge is a
00:1e.0 PCI bridge: Intel Corp. 82801BAM/CAM PCI Bridge (rev 81),
with a graphics chipset
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon R250 Lf [Radeon Mobility 9000 M9] (rev 01)

Although i have /dev/agpgart enabled as a module, as well as both
Intel 440LX/BX/GX, I8xx and E7x05 chipset support
Intel i865 chipset support (AGP_INTEL_MCH)
as modules,

also
Direct Rendering Manager (module) and
ATI Radeon (module)

But i still cannot get any 3D acceleration. glxgears gives me a max of 300fps, when the ATI drivers give me around 2,000 fps afaik. And glxinfo reports

Code:

direct rendering: No
server glx vendor string: SGI
server glx version string: 1.2

Is the problem due to the fact that Intel 82801 chipsets are not supported in linux?

2D works perfectly, and i don't get any crashes whatsoever.

Thanks.

Additional info, here's the whole list for lspci

Code:

root@xushitop:~# lspci
00:00.0 Host bridge: Intel Corp. 82855PM Processor to I/O Controller (rev 03)
00:01.0 PCI bridge: Intel Corp. 82855PM Processor to AGP Controller (rev 03)
00:1d.0 USB Controller: Intel Corp. 82801DB (ICH4) USB UHCI #1 (rev 01)
00:1d.1 USB Controller: Intel Corp. 82801DB (ICH4) USB UHCI #2 (rev 01)
00:1d.2 USB Controller: Intel Corp. 82801DB (ICH4) USB UHCI #3 (rev 01)
00:1d.7 USB Controller: Intel Corp. 82801DB (ICH4) USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corp. 82801BAM/CAM PCI Bridge (rev 81)
00:1f.0 ISA bridge: Intel Corp. 82801DBM LPC Interface Controller (rev 01)
00:1f.1 IDE interface: Intel Corp. 82801DBM (ICH4) Ultra ATA Storage Controller (rev 01)
00:1f.3 SMBus: Intel Corp. 82801DB/DBM (ICH4) SMBus Controller (rev 01)
00:1f.5 Multimedia audio controller: Intel Corp. 82801DB (ICH4) AC'97 Audio Controller (rev 01)
00:1f.6 Modem: Intel Corp. 82801DB (ICH4) AC'97 Modem Controller (rev 01)
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon R250 Lf [Radeon Mobility 9000 M9] (rev 01)
02:00.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host Controller (rev 80)
02:01.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 20)
02:02.0 Network controller: Intel Corp. PRO/Wireless LAN 2100 3B Mini PCI Adapter (rev 04)
02:04.0 CardBus bridge: ENE Technology Inc CB1410 Cardbus Controller

Nobber · 05-09-2005, 09:27 AM

I have found AGP/DRI a tricky thing to get right. On some machines, it only works if you compile support as modules; on others only if support is baked into the kernel. On my laptop (which has a Savage graphics card), AGP/DRI work as modules with kernel 2.6.10, but not with 2.6.11. On one of my desktops (which has an old 3dfx card), I can't get DRI working at all.

Which makes me glad I chose an NVIDIA card for my main desktop, because the (proprietary) nvidia module takes care of AGP and DRI all in one go.

xushi · 05-09-2005, 10:55 AM

Its a pain =/ and i don't want to give up this laptop just because of its lack of propper 3D acceleration. I was hoping it would last a few years.

Is there a really big difference between compiling agpgart as a module, or built in?

tw001_tw · 05-09-2005, 11:21 AM

Xushi - I'm not going to give you too much help with your problem directly, as I'd
most likely lead you astray, but to answer your question:

Quote:

I'm trying to find out what exactly is agpgart.

http://utah-glx.sourceforge.net/gart/README

You only really need to read the top half for the answer. I always thought is was a
kind of 'generic' driver for the agp slot, just to get it going and work with the rest of the
system. I think I was about 25% right on that.

best regards
-tw

p.s. - still wondering what the 'g' in the " 'gart' (*mumble*
address resolution table) " is.

egag · 05-09-2005, 03:23 PM

"graphics " (?)

egag

Shade · 05-09-2005, 05:58 PM

Xushi -- make sure you have tmpfs mounted at /dev/shm

use the command mount by itself to see what's mounted.

If it's not mounted, add this line to fstab

Code:

tmpfs           /dev/shm          tmpfs       defaults,user        0   0

and then issue mount /dev/shm as root :-D

Also check the permissions on /dev/dri/card0 -- you might have to chmod 666 it or add your user to the 'video' group.
--Shade

xushi · 05-10-2005, 03:30 PM

Thanks. I already have tmpfs mounted

Code:

tmpfs           /dev/shm          tmpfs       defaults         0   0

As for /dev/dri/card0, that's a first.. i'm not sure what's its set to at the moment,

Code:

crw-rw----  1 root video 226, 0 2005-05-04 10:54 card0

tw001_tw, thanks for the info =)