https://bugs.freedesktop.org/show_bug.cgi?id=61182
--- Comment #35 from D. Hugh Redelmeier hugh@mimosa.com --- I finally am trying to set the GART size, as per Alex's comment #12.
Without setting it, Xorg0.log reports: [ 15.054] (II) RADEON(0): mem size init: gart size :1fdef000 vram size: s:20000000 visible:1f020000
The default GART size is 512MiB, You'd think that would be a good match for the 512MiB video RAM on my card. This output shows that the GART size is reduced by a somewhat odd number (13^2 * 2^12).
When I set radeon.gartsize=1024 on the kernel line, Xorg.0.log reports: [ 14.842] (II) RADEON(0): mem size init: gart size :3fdef000 vram size: s:20000000 visible:1f020000
Again, the GART size is reduced by the same amount.
Wait: according to http://dri.freedesktop.org/wiki/GART/ the GART seems to enable the video card to access the computer's memory, not the other way around. So I don't see how this is relevant: we're getting a crash in a CPU instruction that is trying to access the video card's memory.