options agpgart agp_try_unsupported=1
line I get syslog of:
Sep 1 23:19:56 domus kernel: Linux agpgart interface v0.99 (c) Jeff Hartmann
Sep 1 23:19:56 domus kernel: agpgart: Maximum main memory to use for agp memory: 690M
Sep 1 23:19:56 domus kernel: agpgart: Detected AMD 761 chipset
Sep 1 23:19:56 domus kernel: agpgart: AGP aperture is 64M @ 0xd8000000
Adding the agp_try_unsupported line was all I can remember doing to there from the same unsupported bridge bridge error (it was 2 years ago).
I think the freezing is unrelated. I had no problems for nearly two years. My freezing problem started recently (at same time as a kernel and memory change). I've tried going back to old nvidia drivers and they all now show the same problem. From the news groups there are others out there with this problem, and no good answers.
Sorry I can't help - I need the answer as much as you!