"Contrast: Off" = default
echo 19 0 > /proc/eink_fb/update_display
I think for now, we don't need to mess with /sys/devices/platform/eink_fb.0/override_upd_mode so just leave it at default 0 (ie: control is on/off)
After more testing, here is my summary:
"Contrast: 7" is a special case of the eInk contrast control, in that it sets the screen to display as 1 bit (hence very dark); This is the only contrast value which doesn't flash by default.
You mention the anti-alias. What I have found is that if after a page is drawn at contrast 7, you issue the following:
echo 19 3 > /proc/eink_fb/update_display ; echo 18 0 > /proc/eink_fb/update_display ; echo 19 7 > /proc/eink_fb/update_display
the anti-aliasing fills in, and the display looks normal. this happens very fast and is not (to me) nearly as visually distracting as the normal method of refresh. the display is not perfect; you can see a slight white-ghosting of the previous page, but to me it is less obnoxious than the flash. life is all about compromises. the good news is that (for me) the ghosting is not cumulative ie: does not get worse over time; so this wouldn't require a complete refresh every 6 pages like nook does.
what we need now is for some l33t h4x0r to write a simple script to monitor page turns and issue the above command or it's equivalent. It would be a great POC if someone could just tail /var/log/messages or whatever and fire whenever the page turns.
seriously guys, this could be awesome. let's do more than change screensavers!