ATI sucks
Since I started using Linux, I’ve always avoided ATI graphics cards, simply because they have historically withheld Linux drivers for certain graphics cards, waiting until the cards were near obsoletion to release compatible drivers — even binary ones. Nvidia, on the other hand, has had a relatively good track record for keeping their binary Linux drivers current. This was really my only reason for staying away from ATI.
Recently, however, I have had some very bad experiences with ATI graphics cards on Linux. My employer recently purchased a couple of LCD monitors for my use; strangely, when using the VGA inputs, the picture on these monitors had too much red and blue (tried different cables, different cards with same results). My main card (AGP, Nvidia Geforce FX 5200) had a DVI output, so that was no problem; but I needed to replace my second PCI Nvidia card. The only cards we had available with DVI outputs were ATI. I grudgingly popped one of these in (a Radeon 7000 64MB).
The very cards — where they belong.
Right out of the gate, everything seemed to be okay. I powered on my machine, added the new device in xorg.conf with the “radeon” driver (I think this is the open source one; I didn’t care about 3D acceleration on the secondary screen anyway), and up came X as I expected. Then I moved a window on the second screen, and the display flickered off for about two seconds and then came back on. Wtf? I looked to make sure everything was on separate IRQ channels and whatnot; yep, no problems there. I tried moving it to a different slot to take up a different IRQ — same problems. I tried another identical card, and saw the same problem.
Oh well, I had another ATI PCI card to try. I replaced the problematic card with the new one (this one a Radeon 9250 128MB), and powered on my computer. It worked okay at first, same as the other one, with the same driver. I moved a window around on the second screen — yay, no more flickering! At this point I just chalked the previous problem up to the Radeon 7000 being too slow, or something.
Time to get down to work on my pretty new LCDs. I put on my headphones, and turned on some music — and nearly went deaf from the horrible static noises produced. Well … something’s broken there. Checked interrupts — everything was on its own IRQ. I tried a few things here: moving the graphics card to a different slot, moving the sound card to a different slot, trying different IRQ schemes in Linux to assign the sound card a higher priority IRQ, etc. The only action that solved my problem was to use the motherboard-integrated sound card, which I had stopped using because of audible interference.
I went back to the first PCI card I tried, since I’d much rather deal with flickering (I rarely moved things on the second screen, anyway) — it no longer exhibited the flickering problem. I must have changed something, but I don’t know what. Over the couple weeks that I used this card, I began noticing a new interference problem on the sound car, when I listened on my headphones. Also, very rarely, and seemingly randomly (except when scrolling in OpenOffice — I could consistently reproduce this), it would flicker a bit just as before. Sigh.
Finally, I asked my employers to buy a cheap ($35) Nvidia Geforce FX 5200 PCI card from Newegg. I just put it in today, and the new card works perfectly. No more flickering (tried OpenOffice on both monitors, flung windows about the screens at lightning speed, resized windows, etc.), and no more interference with sound (I listened intently for several minutes to some quiet music).
Why do these ATI cards cause so many intermittent issues with my hardware? It could possibly be just a bad combination of hardware, and I’m not truly sure where the fault belongs, but given that I consistently experienced problems only when ATI cards were in my system, I place it with them. Take what you will from this post, but I will continue avoiding ATI.