On Tue, 8 Jan 2002, Rodent of Unusual Size wrote:
> Now that I'm using my T21 more and more, I'm leaving it on for longer
> periods of time.  Not as long as I'd like, though, since it seems to do
> a hard hang sometimes.

  I used to have a problem like that, when I was running a buggy X server.
To work around it, I combined two things: The kernel's "Magic SysRq"
feature, and a utility called "vga_reset".

  The "Magic SysRq" feature of the kernel is intended mainly for kernel
hackers, but can be useful for mere mortals as well.  Basically, the Linux
kernel contains a very low-level routine which (if enabled) recognizes
certain key combinations of the form [Alt]+[SysRq]+<letter>.  If there is
anything left of the console driver at all, the kernel should respond to
these commands.

  One useful combination, for example, is [Alt]+[SysRq]+[U], which syncs all
disks and re-mounts all filesystems re-only.  That can come in handy right
before the ole 120-reset.

  However, the particular ones I found applicable to X hangs were
[Alt]+[SysRq]+[K] (kill all programs on the current virtual console (e.g.,
the X session)), followed by [Alt]+[SysRq]+[R] (reset the keyboard and put
it in a sane state).

  This gave me back my keyboard, and let me do things like switch VCs with
[Alt]+[Fn] combos.  I could even log-in and run commands.  However, since
the normal X server "restore screen" cleanup routines never got called, I
was blind -- random colored garbage on the screen instead of characters.

  That is where "vga_reset" came in.  It was part of the SVGALib development
toolkit, IIRC.  It did what it said -- reset the VGA card (complete with
BIOS copyright banner and everything).  Ta-da, I had my console back.  At
that point, I could re-start X, and resume working.

  This is not expected to be a long-term solution, but more of a general
aide in trouble-shooting.  I hope it helps you, or someone.  :)

  (As for why I was running a buggy X server: I was using some VGA card (I
forget what exactly) that was not supported by XFree at the time.  Through
something approaching divine intervention, I found a working (I use the term
loosely) X server on the web.  It consisted of a bare XF86_SVGA binary
hanging out in some directory, without so much as a README.  But it worked.
Sort of.)

-- 
Ben Scott <[EMAIL PROTECTED]>
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