Hi Alex,

Workaround progress : delete xorg.conf; Why ?
According radeon man page :
http://manpages.debian.org/cgi-bin/man.cgi?sektion=4&query=radeon&apropos=0&manpath=sid&locale=en
Option "AccelMethod" "string"
              Chooses  between  available  acceleration  architectures.  Valid
              values are EXA (for pre-TAHITI GPUs) and  glamor  (for  R300  or
              higher). The default is glamor as of TAHITI, otherwise EXA.

By checking my Xorg.0.log, I realized that "EXA" submodule is loaded instead
"glamor" ... (noticed in my workaround firmware non-free installed + mesalib
not patched)
Since my gpu is a R300 (RV380-X600) family submodule should be "glamor", right
or mistake from me due to misunderstanding something ?

Regards and have a nice day,

Kristof