This problem happens with all versions of xorg-x11 > 6.8.99.1 that I tried. That is mostly all of them including up to 6.8.99.11 as of this writing.

• My environment:
  • cpuinfo
  • lspci
  • xorg.conf
• Enabling matroxfb and running xorgcfg or startx causes the following to happen:
  • The screen blanks and the monitor displays a message that it is being set in 60Hz vertical refresh mode. I have specified the following in my xorg.conf, which I am positive are the correct numbers.

    Section "Monitor"
    	Identifier   "Monitor0"
    	HorizSync    30.0 - 96.0
    	VertRefresh  50.0 - 160.0
    	DisplaySize  380 285
    	Option       "dpms"
    EndSection

  • X logs the following message repeatedly (refer to Xorg.8.log)

    (EE) MGA(0): [dri] Idle timed out, resetting engine...

  • Pressing Control+C does not kill the Xorg process
  • I cannot get any image on the console in any way
  • If I ssh from another machine, I can kill the Xorg process with "kill -9" only; The display is still unavailable, though, and a restart is needed
  • If I do not kill the Xorg process, the machine hangs and only a cold reset can get it up again. This happens within a minute.
  • The files in this directory are the relevant logs after I did the following:
    • boot
    • modprobe drm with debug output
    • run xorgcfg
    • ssh from another machine
    • kill -9 the Xorg process before it hung the machine
    • I gathered the information and type this file on the broken machine without having restarted yet. Still ssh-ed, though, because the display is unavailable.
• Disabling matroxfb (actually disabling FB completely in the kernel) caused the following:
  • X does not freeze and display all those errors
  • startx even started up, but my windowmaker display was more than garbled (no background, no buttons, only a vague shade where one button is supposed to be)
    

    BEFORE	AFTER

  • Killing X normally (Control+Alt+Del to bring up the quit dialog of WindowMaker and pressing enter) left me with a garbled console:
    

    BEFORE	AFTER	running "clear"

  • Downgrading X while still in the garbled console, etc-update (and "-5" responding to the unreadable prompt), and running startx again worked. The display was still garbled (some lines were funny but it was at least readable).