display resolution mismatch on chromebook

gistfile1.txt

Connecting a 2012 samsung chromebook XE303C12 ($249 ARM-based model) to a Dell E2209W 22"
widescreen LCD monitor (using a DVI to HDMI cable) produces inconsistent resolution
detection for the external monitor.  The E2209W reports it's optimal resolution
(when connected to the chromebook) to be 1680x1050@60Hz, but often syncs at 1788x1050@60Hz.
On my system, this produces a black stripe on the right side of the screen.  The state of
the external monitor (on/off, connected/disconnected) at boot-time determines whether
or not the resolution will successfully sync to the optimal setting.  Through
trial-and-error, I've determined that the following sequence always lands on the optimal
monitor resolution:

1.) With chromebook powered off, connect monitor via DVI-HDMI cable but do not power on the
monitor.

2.) Boot the chromebook.  You will see the white chrome splash screen, then the screen will
go blank.  The chromebook is sending the display to the external monitor even though it is
not powered on (another bug, or part of the same issue).

3.) Power on the monitor.  Resolution will sync to the optimal value and the display image
will fill the whole screen.

Note: switching between external and on-board displays using the keyboard control sequence
will trigger the failure mode.  To recover, the chromebook must be powered down and the
above sequence repeated.