Finally I've managed to get full resolution RAW image without closing the shutter.
All you need is:
1. Disable sensor polling for EVF (the simplest way is enter to Canon Menu).
2. Execute "Capture.Create" event procedure.( Don't need for "Capture.WholeParallel")
3. Execute "Capture.WholeParallel" event procedure.
4. Take raw data from RAM. (on EOS M3 there is only one raw buffer for it. Its address can be found at the beginning of "Capture.WholeParallel" function)
You can also use "Capture.WholeSerial" to take picture with shutter.
Is EVF = "Electronic View Finder".
Do you have a M3 "Electronic View Finder".
Last Time I used my M3 "Electronic View Finder" with CHDK the EVF was not syncing,
so the EVF was un-usable.
i.e. EVF functions are not implemented or tested in CHDK.
(For M3-101a & M3-Latest)
Also what are you then doing with the full resolution RAW images.
Edit #1 Some after thoughts on EVF and the one M3 raw buffer (see the above).
a/ Is there also a HDMI buffer or is it shared with one raw buffer.
b/ There is lots of pins on my EVF M3 Viewfinder, so just guessing, that it may be its also some type of HDMI interface.
c/ Is there also a Wi-Fi Remote Live View buffer or is it shared with one raw buffer.
d/ When using Wi-Fi Remote Live View via a Smart Phone/Tablet the Cameras Viewfinder and HDMI is then disabled.
e/ "...You can also use "Capture.WholeSerial" to take picture with shutter..."
Is it also disabled when using when using the Wi-Fi Remote Live View.
Also do you have any (detailed) photos of the HDMI interface IC & EVF interface IC.
[Could the Camera Display interface IC also be HDMI any ,detailed, photos.]