Dual-head Xinerama problem after latest XFree86 update

[sub1 shrike lists redhat msquared id au]

Hi everyone.

I just updated my packages via up2date.  Among the updates were XFree86
packages (I'll give a full list at the bottom).  Somehow the update caused
the following two strange behaviours:

  1.  Primary and secondary monitors swapped over
  2.  Secondary monitor no longer comes out of standby after powerup

The first problem was easy to solve: swap the monitor cables over on the
card.  :-)  The second one was a lot harder, since as far as the software
was concerned, nothing was wrong.  Xinerama was working, I had a desktop
spanning both monitors, and I could still log in and do things, I just
couldn't see what was on my secondary monitor (previously on the right,
now on the left).  The monitor itself wouldn't come out of standby mode.

At first, I thought I might have killed the monitor, but swapping monitors
caused the other monitor to stay in standby.  I also thought I might have
killed the secondary connector on the card, but I eventualy found a
workaround that showed everything in the hardware was OK, it's just that
the update did something strange.

After giving up and deciding that Xinerama wasn't going to work any more,
I switched back to two desktops (turned Xinerama off, but kept dual-head
config).  That also failed to bring the secondary out of standby.  I
resigned myself to single-monitor until I could fix the card, so I turned
off dual-head mode.  Suddenly, the secondary monitor came to life, and was
displaying a clone of the primary monitor!  I switched back into dual-head
mode, and the monitor stayed on.  So, my workaround is this:

  * Turn on machine
  * Switch to single-monitor mode
  * Restart X
  * Switch back to dual-head mode
  * Restart X

That's it!  Everything will be fine from then on until the next reboot or
poweroff.

I figured this is probably an XFree86 bug, so I searched XFree86's
Bugzilla and found this:

  http://bugs.xfree86.org/show_bug.cgi?id=443

I posted a couple of amendments, but they suggested I either post another
separate bug (since I have a Matrox G550, not an ATI Radeon IGP 320M), or
check with RedHat, since it was after a RedHat update that the problem
occurred.  So, I thought I'd first post here to see if anyone else has had
this problem, either with a Matrox G550 or with any other dual-head setup.

Based on the symptoms, it seems that the secondary monitor is not being
correctly initialised when dual-head is turned on.  I figure this since
switching to single-monitor turns on the secondary monitor and switching
back to dual-head doesn't turn it back off.  Comments, anyone?  Similar
problems or experiences?

Regards, Msquared...