Xscreensaver issues with IBM Thinkpad R40

[nhaggin]

Greetings, all. I apologize profusely and abjectly in advance if this post is massively redundant; a couple different searches turned up nothing like this, and although parts of the answer may be buried therein, my eyes glazed over whilst reading the gigantic Radeon sticky thread. (Lots of great information but quite unorganized.)

Some of the GL modules in xscreensaver have been troubling me on my brand-spanking-new (got it on 2 January) IBM Thinkpad R40, whose relevant specs are as follows:

2 GHz Celeron
1024 MB RAM
Radeon Mobility M6 LY with 16 MB of video RAM.

I have noted two separate failure modes:

1. When running an X server compiled against 2.4 under 2.6, most modules will display three or four frames and then freeze the machine. The mouse still moves but I get no action on the keyboard (can't even CTRL-ALT-Fn to switch to another virtual console).

2. When running an X server compiled against the current running kernel (2.4 or 2.6), I will be able to view GL screensaver modules five or six times in a row. On the sixth or seventh invocation, the screen will be black; nothing will display at all, and the keyboard will again freeze.

I'm using kernel versions 2.4.22-gentoo-r3 and 2.6.0. In 2.4.22 agpgart and my chipset driver are compiled in, DRI support is NOT built, and I emerged xfree-drm to get the Radeon modules. In 2.6.0 agpgart, my chipset driver, and DRI support are all compiled into the kernel, and I built the kernel's Radeon module. AGP support shows up in dmesg, and glxinfo shows that direct rendering is, in fact, enabled. (As a side note, glxgears gives me 274 FPS in a normal-size window; this is one other thing I'm trying to increase, so far without success.) I have the following options set for the Radeon driver in XF86Config: