[h-e-w] Update: Workarounds for emacs on Windows 7

[John J. Xenakis]

I sent the messages below a couple of months ago, describing a problem
that occurs with emacs on Windows 7.  At that time, it was suggested
that the bug was fixed in the new version of Emacs, so I didn't
worry about it.

However, I installed version 24.1.1 a month ago, and after
452 hours of elapsed time, the same problem occurred again.

Since then, I've also received a private message from another
emacs user having the same problem.

Emacs users on Windows 7 should be aware of this problem, so that
they won't unnecessarily reboot their systems.

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*** First message

I've used emacs on several different systems, including different
flavors of Windows and xemacs on Linux, with pretty much the same
macro set, which has been very convenient.  I use multiple frames and
multiple windows very heavily on a day to day basis.

Starting late last year, I started working on a Windows 7 system, and
emacs worked fine, as usual.  However, after about 7-10 days of
uptime, Windows 7 freaked out with all application windows blinking
and moving around all over the place.  At first I thought it was a
Windows 7 bug, caused by one of my display settings, and I had to
reboot the computer.  But after it's happened several times over a few
months, I've finally concluded that it's an emacs bug.  It took me a
long time to find this out, since the bug occurs so infrequently.

Since I'm running 64-bit Windows, what it looks like to me is that
emacs is using some 64-bit counter as a 32-bit or 16-bit counter
that's cycling around to zero after several days of heavy use of
emacs.  Somehow, this is causing all the application windows on the
screen to be screwed up or start blinking like mad.

People using 64-bit Windows 7 should be aware of this bug, and be
prepared for it.  The workaround is to close and reopen emacs (you
don't have to log out or reboot).  This is a lot harder than it
sounds, with windows freaking out and you can't find where your emacs
window is.  But if you can bring up the task manager, you can kill
emacs.  What I had to do was to create an abort macro, assigned to
keystroke ctl-alt-f1, that creates a quick recovery file and exits.
If you do that, then all you have to do is remember where your emacs
window was, click on it, and launch the abort keystroke.  Once emacs
exits, all your other application windows are ok again.

---

*** Follow-up message:

Here are some additional details:

* I'm using emacs 23.4.1 on 64 bit Windows 7.

* I start emacs from a DOS command line batch file with the command
    "c:\xx\emacs-23.4\bin\runemacs" --no-splash --load c:\jx\emacs\init.el

* The same problem occurred at another client with different
  application software running on a 64-bit Windows 7 system.  (One used
  Visual Studio with C#, the other uses Eclipse with Java.  I used
  Firefox on both systems.)

* The bug has occurred about 6-10 times since last September.

* I typically have 4, 5 or more frames open, each with two or more
  windows, so I'm a very heavy GUI user.

* The bug never occurs in less than a week of uptime, and often not
  until two weeks of uptime.

* On two or three occasions, the bug was triggered when I was
  scrolling through code.

* It's the last three items that led me to propose that there's a
  16-bit or 32-bit counter that's cycling around to zero.

* I run emacs on another Windows 7 system that acts as a kind of
  server.  The problem has never occurred there, which I attribute to
  the fact that it's a server, and the GUI is seldom used.

* I also run the same version of emacs on a Windows XP system with no
  problems.

---

*** Private message from another emacs user

I saw your posting, and am running into an identical problem every
week or so with emacs windows freaking out graphically but continuing
to run otherwise.  Just wanted to give you the details of my setup in
case you got feedback from others to narrow down the problem.  If
you'd like any more specifics about my configuration, let me know and
I'd be happy to provide them.

Windows 7 64-bit
Emacs: M-x emacs-version returns: GNU Emacs 23.1.1
(i386-mingw-nt6.1.7600) of 2009-07-29 on SOFT-MJASON
Running dual monitors, Nvidia Quadro FX 1800, Driver version
8.16.11.9175 (ca. 2009)
Also running another program linked against
c:\windows\system32\GDI32.dll: Q-Dir 4.94 -- WinXp-like explorer clone
that makes it a little easier to work under Windows 7.  Not sure if
these might be poorly interacting with each other.

-----

John J. Xenakis
GenerationalDynamics.com

John J. Xenakis
100 Memorial Drive Apt 8-13A
Cambridge, MA 02142
Phone: 617-864-0010
E-mail: address@hidden
Web site: http://www.GenerationalDynamics.com
Forum:    http://www.GenerationalDynamics.com/forum