> I can only reboot with SysRq + R E I S U B
Does that mean all of these reboot: SysRq + R, SysRq + E,...?
We do not know for sure whether it is ACPI, right?
> and after some minutes the system freeze.
Hmm, could you try to boot with: CPUFREQ=off boot param (hope this is the right one).
Which graphics driver are you using, could it be related to fglrx or radeonhd?
Try the other one, or frambuffer X driver.
> I can only reboot with SysRq + R E I S U B
Does that mean all of these reboot: SysRq + R, SysRq + E,...?
We do not know for sure whether it is ACPI, right?
> and after some minutes the system freeze.
Hmm, could you try to boot with: CPUFREQ=off boot param (hope this is the right one).
Which graphics driver are you using, could it be related to fglrx or radeonhd?
Try the other one, or frambuffer X driver.