For normal boot you can fix temporarily the problem until the bug fixed by changing your "/etc/X11/xorg.conf" by this (this is the failsafe conf) :
Section "Device" Identifier "Configured Video Device" Driver "Vesa" EndSection
Section "Monitor" Identifier "Configured Monitor" EndSection
Section "Sceen" Identifier "Default Screen" Monitor "Configured Monitor" Device "Configured Video Device" EndSection
For normal boot you can fix temporarily the problem until the bug fixed by changing your "/etc/X11/ xorg.conf" by this (this is the failsafe conf) :
Section "Device"
Identifier "Configured Video Device"
Driver "Vesa"
EndSection
Section "Monitor"
Identifier "Configured Monitor"
EndSection
Section "Sceen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
EndSection