HDMI-connected flat panel keeps blanking

[Robert P. J. Day]

  i just HDMI-connected a gateway flat panel display to my f12 laptop,
and configured the display to span.  in short order, i got the
standard f12 desktop background to display on the flat panel and, yes,
i can move the cursor off the right-hand side of my laptop and watch
it magically appear on the left-hand side of the flat panel.

  the problem is, the flat panel keeps blanking -- literally every
several seconds -- and then comes back.  does this output from xrandr
look reasonable?

# xrandr
Screen 0: minimum 320 x 200, current 2560 x 800, maximum 8192 x 8192
VGA-0 disconnected (normal left inverted right x axis y axis)
LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis)
0mm x 0mm
   1280x800       60.0*+
   1280x720       59.9
   1152x768       59.8
   1024x768       60.0     59.9
   800x600        60.3     59.9     56.2
   848x480        59.7
   720x480        59.7
   640x480        59.9     59.4
HDMI-0 connected 1280x800+1280+0 (normal left inverted right x axis y
axis) 442mm x 249mm
   1600x900       59.9 +
   1280x800       59.8*
   1152x864       75.0
   1280x720       60.0
   1024x768       75.1     70.1     60.0
   832x624        74.6
   800x600        72.2     75.0     60.3     56.2
   640x480        72.8     75.0     66.7     60.0
   720x400        70.1

the setup seems correct, except for the persistent blanking.
thoughts?

rday
--

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Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
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