Newer ATI Display Cards
ATI Cards up to the ATI 9500 are well supported within Xorg 6.8 (CentOS 4) or XFree 4.3 (CentOS 3). These cards are supported by either the ati driver or the radeon driver (depending on your card). These cards should be detected automatically upon installation.
If you have problems getting your card to run because it is a newer card, you should think about using the proprietary ATI driver.
Mind you, this is a driver without sources to it and you'll probably won't get any support if you run this driver.
Your ATI graphics card isn't detected on install, because your Card is too new. You cannot run X or X runs with the VESA driver, which is slow.
3. In-Depth explanation
Newer ATI graphics cards (9500 and above) (FIXME: Is that true?) are not supported by Xorg or XFree yet, or the support isn't very stable. 2D support might work, 3D support doesn't (for example the R300 driver).
4. Output of `lspci -v`
Example output (I only have a R250 card, which is well supported):
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon R250 Lf [FireGL 9000] (rev 02) (prog-if 00 [VGA]) Subsystem: IBM Unknown device 0531 Flags: bus master, stepping, fast Back2Back, 66MHz, medium devsel, latency 66, IRQ 11 Memory at e0000000 (32-bit, prefetchable) [size=128M] I/O ports at 3000 [size=256] Memory at c0100000 (32-bit, non-prefetchable) [size=64K] [virtual] Expansion ROM at c0120000 [disabled] [size=128K] Capabilities:  AGP version 2.0 Capabilities:  Power Management version 2
Go to ATI Driver Homepage for Linux.
Select your Architecture (i386 or x86_64 only) and your graphics card.
Download the "ATI Download Installer" (although that package is bigger than the pure driver packages).
Now you have two options: If you have X running, launch the driver installer in an xterm, if you haven't X running, launch it in a console.
sudo su - sh ati-driver-installer-version-arch.run
The program will spew out some information and start either a graphical installer or a console program. Both programs work the same, so I'll explain the console version here (no fancy screenshots!)
After startup the installer asks you several questions:
The first box just states which system has been found, you should see a mention of glibc-2.1 and Red Hat in there. Click OK.
You're then opted two installation choices. Choose "2. Generate Distribution Specific Driver Package"
Click "OK" on the next screen (you can't really do anything else there).
Read the license (if you want to), click EXIT and say YES when you are asked to agree to the License. If you don't, the installation will stop.
When you are asked to choose the installation path, stay with the suggested "/". Click OK.
The next page is broken. Make sure that the select box has an [X] in it. Click OK.
Select "RedHat Packages ( )". Click OK.
Now wait while the installer generates the package.
You will then find a package named fglrx-something.rpm in the directory you started the installer in.
This package can be installed with rpm -Uvh fglrx-something.rpm
After that save /etc/X11/xorg.conf on CentOS 4 systems or /etc/X11/XF86Config on CentOS 3 systems.
After that run the program aticonfig. This will ask you several questions about your system which you have to answer accordingly. As this depends very much on the system you are running aticonfig on (and as I don't have that driver installed at the moment), I will not post the pages of output here. If you do something wrong, you can always run aticonfig again.
FIXME: If anyone wants to, send me the output of aticonfig and I put it here
Find the line that reads
If you have the first version, change the "5" to a "3" before rebooting.
After that you should reboot your system, so any loaded radeon or vesa drivers get cleaned out. If you answered all questions correctly, X should run.
You can verify this with running startx. If X doesn't start, please look at the output it spews at you. You probably did something wrong when running aticonfig.
If X does run, you can change the line in /etc/inittab to
Then X will be started automatically at bootup.
Several ATI cards should run with the vesa X-Driver, if you do not need the advanced features.
The output of aticonfig really should be read and answered very carefully.