Linux 3D AGP GPU Roundup: More Cutting Edge Penguin Performance

Let's Talk about Drivers

Installing a dozen video cards with various sets of drivers was the largest annoyance for us during the testing of this review. Obviously, due to license restrictions, NVIDIA and ATI drivers must be installed after the initial OS installation, and cannot be packaged with the kernel. For Windows users not familiar with the process, the kernel module or driver wrapper must be completely recompiled for closed source drivers to work.

NVIDIA's drivers are not only supported via SuSE's YOU (the YAST Online Updater), but the drivers easily plug into SuSE without any trouble. We just installed our kernel source, hit init 3, ran the 1.0-6111 binary install, and then followed the instructions on the screen. NVIDIA's drivers provide DRI-like support via SaX2 (the SuSE X configuration tool) as well. Typical video cards us the Direct Rendering Infrastructure (DRI) for 3D accelerated graphics. The DRI acts as somewhat of an abstraction layer between X Windows and OpenGL. NVIDIA actually uses their own DRI-like module outside of the standard DRI module. Without DRI or NVIDIA's modules, we are only running software acceleration.

ATI's drivers came out of the box with several problems. We made the initial mistake of installing and testing the entire suite of video cards with the NVIDIA cards/drivers first. We are not entirely sure why, but even after completely removing the NVIDIA kernel module via NVIDIA's uninstall scripts, we still had persistent errors installing the ATI drivers correctly.

Our first test bed was an nForce3 MSI Socket 939 board. We isolated some of our problems to the agpgart module - for older ATI drivers, we need to load a separate specific AGP module on SuSE 9.1 for DRI to load correctly. On our MSI nForce3 board, this should have been the nvidia_agp module. However, try as we could, we could not get nvidia_agp and fglrx to play well with each other. Some of the issues stem from SuSE 9.1 not recognizing the nForce3 chipset correctly, but some issues may stem from ATI drivers just not recognizing everything correctly. After switching to a Socket 939 VIA motherboard, our problems suddenly disappeared. Of course, we had to re-test our entire NVIDIA suite on the new motherboard (we saved it for last the second time around).

Even by switching to a different motherboard, we were not entirely blessed. Using ATI's driver set from their website yielded some results, but first, we made the mistake of using the fglrx package from ATI's website. ATI's implementation of the X Windows configuration completely upsets SaX2, and X will simply ignore the DRI module when we try to load it. Somewhere between playing with various kernel builds, driver builds and hardware configurations, we finally got it right. Our best success with newest SuSE 9.2-RC3 kernel^[1] came from using the RPMs and instructions on the supplement FTP site. The 2.6.8 kernel blew away our boot configuration a few times; for whatever reason, VIA SATA controllers are now recognized as SCSI controllers to the new Linux kernel. Without getting too much into detail, we needed to re-edit our mtab, fstab and grub configuration to a different device; the serial ATA drives suddenly became SCSI drives. We finally no longer had errors on the agpgart driver:

linux:~ # dmesg | grep agpgart
Linux agpgart interface v0.100 (c) Dave Jones
agpgart: Detected AGP bridge 0
agpgart: Maximum main memory to use for agp memory: 941M
agpgart: AGP aperture is 128M @ 0xf0000000
linux:~ #

Footnote
[1] 2.6.8-14-default, you can download it from the SuSE FTP site in the update directory.