Ctrl-Alt-F? Bindings Broken Under Xen 3.0.3-142.el5_9.1 / 2.6.18-348.1.1.el5xen?

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I am not sure what I did, but for some reason Ctrl-Alt-F? bindings are broken on 64-bit xen desktop machine (but not on my laptop (32-bit, no xen)). Both machines are (mostly) up-to-date and running CentOS 5.9. I rarely hop to different Virtual Consoles (eg Ctrl-Alt-F1 … Ctrl-Alt-F7), but today I wanted to go to the main console to watch some kernel verbage (I was checking something with hot-swap SATA disk). I discovered that I could not switch back to my X11 session
(Ctrl-Alt-F7)! I did some googling, but did not find anything. So far as I can tell, I can switch to one of the other VT (Ctrl-Alt-Fn) *from*
VT7 (my X11 session), but cannot then switch to any other VT from there, using the Ctrl-Alt-F? key bindings. The chvt command works, but the keybindings don’t. It is most strange. I know this used to work
(and still does work just fine on my laptop, running much the same system, including the same X11 configuration, with the same desktop setup (plain fvwm in MWM compatibity mode, same keybindings, etc.). Other than different video cards (and thus different X11 drivers) and
32-bit vs 64-bit and with xen virtualization on the 64-bit desktop box, the system setups are virtually identical.

2 thoughts on - Ctrl-Alt-F? Bindings Broken Under Xen 3.0.3-142.el5_9.1 / 2.6.18-348.1.1.el5xen?

  • OK, some more information:

    I rebooted to a non-xen kernel (2.6.18-348.1.1.el5), and the problem remains, so it is not xen or a xen kernel issue. The machine has an AMD
    64-bit processor (AMD Sempron(tm) Processor LE-1300), if that makes any difference. I have a LD450 keyboard (DEC VT220 flavored ps2 keyboard). The keyboard does work: the X server properly intercepts Ctrl-Alt-Fn and does a proper chvt call. The *kernel* itself is not handling Ctrl-Alt-Fn. (It is handling Ctrl-Alt-Delete, but I suspect that is something completely different.)

    My 32-bit laptop, running kernel 2.6.18-348.1.1.el5 is working just fine
    — the kernel there is properly handling Ctrl-Alt-Fn and switches between consoles without problems.

    Oh, both machines boot to runlevel 3 and I use startx to fire up X (I
    loath graphical logins).

    At Wed, 20 Mar 2013 13:26:14 -0400 CentOS mailing list wrote:

  • The graphics chip is probably relevant. FWIW I can’t Ctrl-Alt-Fn to any Virtual Console (I just get a black screen, no login prompt). I
    have a nVidia graphics chip. There are many reports on the Internet of trouble with VC and nVidia and some other graphics chips.