I've been unable to switch to a VT with the radeon driver ever since it supports the R5xx. No such issue is present with radeonhd.
Today I discovered that disabling page flipping solves it.
With PageFlip disabled, I can switch between VTs and X without problems and the previous font corruption problems I had are nearly gone (they do still happen from time to time).
I'm currently using EXA, with drm also compiled from git, although I'm still on xorg-server 1.3 and mesa 6.5.2. Besides, I'm not using any composite manager although I have it enabled (no noticeable difference whether I enable or disable it).
TextureVideo seems to work but I get lots of:
reported whenever I play a video over xv, and, from there on, X is much much slower.
(EE) RADEON(0): ADVANCE_RING count != expected (46 vs 44) at radeon_textured_videofuncs.c:475
The only options I have enabled on xorg.conf are EnablePageFlip to off, AccelMethod to EXA and SWcursor to on (sometimes my cursor got corrupted and there was no way to fix it besides rebooting).
Accelerated EXA DFS is also working.
Font rendering had never been this fast on this computer
I also get quite a few:
with xxx being mostly 1000.
(II) RADEON(0): Delay xxx usec
Furthermore, I got so many DEBUG outputs from CailReadATIRegister & CailWriteATIRegister on X startup that I just commented them out on the source. They made my Xorg.0.log grow by a 10x factor!!
It just looked like complete garbage since the value were always the same, 10002 or 20002, in a 20%-80% relation (approximately).
The only other line worth mentioning from the X's logs is:
(WW) RADEON(0): Failed to set up write-combining range (0x80000000,0x10000000)