[arch-general] recent upgrade has messed up x

[Scott Weisman]

Until last week, my X setup worked fine. No special configuration needed.

I have a 3rd generation Core i7 notebook with a dual monitor setup.

After a recent update, everything works differently, and not for the better.

Before, with a VGA monitor plugged in (with or without a second HDMI
monitor), the system would boot and output the console display to both the
VGA and LCD. Default X startup was to display at full screen resolution and
also output to VGA and LCD. Now, no matter what, it only outputs to LCD.

The xrandr command to go to dual monitor used to switch within a few
seconds at most. Now, it FAILS the first time. All screens are blank. I
then do a second xrandr to output only to external VGA, which succeeds.

I see this output from the previous command:

X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  21 (RRSetCrtcConfig)
  Serial number of failed request:  39
  Current serial number in output stream:  39

A third xrandr command to once again go to dual then works.

However, the transition takes MUCH longer.

And there are further problems. I have seen the HDMI screen occasionally
blank (the VGA screen is unaffected) for many seconds, then just go back
on. When the screens blank from lack of activity, the time to turn on is
also much longer than the previous 1 or 2 seconds.

The HDMI screen has a great deal of "flicker" (it's not actual flicker,
it's horizontal lines flashing) that just doesn't stop.

No X packages were updated recently. But there was a kernel update from 4.3
to 4.4.

I had zero problems before. Can anyone suggest some fixes? Would be much
appreciated.