Bug 10510 - Xorg should use a more unlikely key combination than Control-Alt-Backspace as the server zap key
Summary: Xorg should use a more unlikely key combination than Control-Alt-Backspace as...
Alias: None
Product: xorg
Classification: Unclassified
Component: Server/General (show other bugs)
Version: unspecified
Hardware: All All
: medium normal
Assignee: Xorg Project Team
QA Contact: Xorg Project Team
Depends on:
Reported: 2007-04-02 14:06 UTC by Jason Spiro
Modified: 2009-04-12 01:29 UTC (History)
3 users (show)

See Also:
i915 platform:
i915 features:


Description Jason Spiro 2007-04-02 14:06:39 UTC
== Background ==

Every day, many users press Control+Alt+Backspace by accident.  There is some
example evidence of how this is so are at the bottom of this bug report.  You marked bug 10507 ("Ctrl-Alt-Backspace should request confirmation before killing Xorg") as WONTFIX, so I am filing this new bug instead.

== Feature request ==

Xorg should have a config file option to make it harder to kill it than a mere Ctrl+Alt+Backspace.  Perhaps Control+Z+A+P all at the same time would be a better key combination.  Yes, that's those four keys held down at once.

Or perhaps Control+Alt+Z, then Control+Alt+A, then Control+Alt+P.

Or maybe you could instead use the key combo Control+Alt+Backspace pressed three times.  The first and second time you press it, the PC speaker would emit a beep and the keyboard Caps/Num/Scroll Lock LED would blink a few times and X would attempt to show a warning dialog on the screen.  The third time you pressed it, X would die.

Although it seems few distributors use DontZap by default, perhaps they would use this new option if it were implemented.  Or maybe you yourself could enable it by default.

== Example evidence ==

"We routinely use backspace to kill a character, C-backspace to kill a word,
C-x backspace to kill a sentence, etc. And inevitably, we press C-M-backspace
trying to kill an s-expression, just to find ourselves wondering why the screen
suddenly turns black for a moment before the login screen appears again. Yup,
we zapped the X server, because that is what C-M-backspace does."
--http://www.foldr.org/~michaelw/log/programming/lisp/dontzap-emacs (Emacs's C
and Java modes use the Ctrl+Alt+Backspace key combination to delete the
{}-enclosed structural block to the left of the cursor.)

"How can I configure X not to shutdown when I accidentally press
control-alt-backspace?  This happens a lot, believe it or not, while I'm using
emacs.  If X were to pop up a confirmation dialog, that
would be even better." --

"In the terminal programs I use, alt-backspace erases the word to the left of
the cursor.  This is very handy, but when my thumb slips just a small amount it
also presses the ctrl key..." --

"A word to Alt+Backspace and Shift+Alt+Backspace: I have noticed the danger of
shutting down X-Windows when you accidentally hit Ctrl+Alt+Backspace instead of
one of the two other keystrokes. So, this might be arguable that users might
accidentally mistype a keystroke thus losing some work (as I did :-))" --

With sticky keys: "I crashed my system accidentally - I wanted Ctrl-Backspace,
and got
Perhaps sticky keys should not stick the combinations:
Ctrl-Alt-[Del|Backspace|Esc]" --

For more examples see:
Comment 1 Elisée Maurer 2007-09-06 02:26:55 UTC
I'm confirming requesting pressing twice or (even better) three times on Ctrl + Alt + Backspace to kill the server would do no harm to those seeing it as an emergency exit function, and would probably save most people from activating it by error. _Trying_ (when X isn't crashed) to show a modal box to explain the user what he did the first time and what will happen if he insists pressing these keys, with a cancel button or whatever would be _really nice_. Please, think about it.
Comment 2 Felix Miata 2008-09-22 20:40:53 UTC
Distros can decide if C-A-BS is too easy, and make the "DontZap" option in xorg.conf the default behavior, as can admins. OpenSUSE has already done it. Please don't change the current keystroke combination that kills X.
Comment 3 Jason Spiro 2008-10-19 09:42:56 UTC
Now that Xorg trunk has server zapping disabled by default, distributors will probably package Xorg and leave zapping disabled by default.  If they do so, then there will no longer be any need to fix this bug.
Comment 4 Daniel Stone 2008-10-21 08:57:53 UTC
On Sun, Oct 19, 2008 at 09:42:57AM -0700, bugzilla-daemon@freedesktop.org wrote:
> Now that Xorg trunk has server zapping disabled by default

 -> WFM
Comment 5 Roc Vallès Domènech 2009-04-11 18:02:45 UTC
Please revert this change.

I expect C-Alt-BS to work, so does everybody else who has ever used it.
Comment 6 Peter Hutterer 2009-04-12 01:29:29 UTC
(In reply to comment #5)
> Please revert this change.

> I expect C-Alt-BS to work, so does everybody else who has ever used it.

please, please, do not infer other peoples opinion from your personal opinion.

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