Lost right edge of display

[Ken Moffat]

One of my machines (an AMD A10 Kaveri, using the radeon driver) is
connected to an AOC 19" 1600x900 monitor.  The monitor was cheap-ish,
I did not realise it had no controls - in future I will have to
remember that you get what you pay for.

When I boot linux (last build was in November, using current
releases), the initial tty display is ok - old-style [OK] markings
from the initscripts are at the right of the display.

But when I use X the right edge of the desktop is lost - perhaps
about 16 pixels, enough to lose the 'close' icon on a window at the
right edge of the desktop.

I have managed to lose the "everything full" brightness with xrandr,
but I am unsure how to try to address the display size.  I suppose I
need to use a modeline ?  If so, are there any pointers to creating
one ?

Back in the day (years ago, before KMS) I sometimes had similar
problems, but I was able to use the controls on the monitor I was
using to adjust things.  Now, no controls - progress.  Not.

TIA

ĸen
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