Late Night PC

I've had a problem twice now with my new system. It's an AMD Athlon X2 4200+ with an Asus M2NPV-VM motherboard running OpenSuse 10.1 Linux. What happens from my point of view is that the display locks up, that is the image is frozen - doesn't move, and the mouse pointer won't move. It doesn't respond to keyboard input either. Once there was sound playing (from two sources) and it just looped one second of audio endlessly. I tried pinging it from another machine on my LAN and there was no response (after I rebooted I could ping it, so I know it's pingable). The first time I was surprised that some little game I was playing was able to lock up Linux. The second time the symptoms were identical but I was running mostly different applications.

I leave this computer on all the time so if this were happening often I'd expect to come home and find it locked up. That hasn't been the case - when I'm away from home I occasionally ssh in and have no issues whatsoever.

So I set about digging and this is what I've found so far. Stephen Olander Waters wrote

Check the top of your dmesg for any warnings about "aperture size". I kept getting freezes because my AGP aperture was too small (32MB) for what Linux wanted (64MB) on a Radeon 9200 256MB.

So I did just what Stephen suggested, I ran
copper:~ # dmesg | less
And found the following message (type /apert in less to search and q to quit)

I looked through the manual for the M2NPV-VM but there's nothing I can see that advises on what aperture size to use, nor is there anything saying how much memory the onboard video card (an Nvidia GeForce 6150 GPU) uses or would like to use. So I'll have to just guess. I've got 2GB of RAM so I'll bump it up as high as I can (though I don't know if the aperture size actually reflects RAM used, I don't much care to find out right now). There's an option I remember seeing in the BIOS to set the aperture size, now I'm going to have a peak and see what I can tweak it to.

(Rob pokes around in some BIOS settings for a while then comes back disheveled and a little harried)

So what I'd seen in the BIOS settings was actually a setting for Frame Buffer Size, not Aperture Size. I tried the Ctrl-F1 trick that's supposed to show some hidden settings in an Award BIOS but I didn't see anything new. I don't know if they actually mean Frame Buffer here in the strictest sense of the term or if they're actually referring to the total amount of sytem RAM that's reserved for the video card. A Frame Buffer is a very specific part of the memory on a video card, I think it's the final picture that's shown on the display after all the other effects are taken into account. When there's processing happening on a 3D graphics card, some of that processing uses other buffers too, like z-buffers for depth information and stencil buffers to apply masks and other stuff.

I snapped some photos of the steps of changing the Frame Buffer size so you can have a look

I adjusted the Frame Buffer size up to the maximum of 128MB (note: this changes in a later version of the BIOS). The message still shows up from X saying that the apperture size is too small, so I'm going to look into updating my BIOS. Check back, I'll write about that too.