I am also experiencing this issue after upgrading Xorg and radeonhd today. Like Yannick I am not showing any write-combining entries in /proc/mtrr, but unlike him I am not having any problems with regards to memory modules. My /proc/mtrr is showing:
reg00: base=0x100000000 ( 4096MB), size= 512MB, count=1: write-back reg01: base=0x120000000 ( 4608MB), size= 256MB, count=1: write-back reg02: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back reg03: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back reg04: base=0x0c0000000 ( 3072MB), size= 256MB, count=1: write-back reg05: base=0x0cff00000 ( 3327MB), size= 1MB, count=1: uncachable I am fairly sure I had a write-combining entry in there before. Is the new version not adding a proper mtrr entry for the framebuffer? Thanks, -Damien
