Calibrating MacBook Pro w/ i1 Pro. Which LED display technology is it?

Question

Hi all, I'm trying to calibrate for photography my MacBook Pro 6,2 with a high-res matt screen using the i1 Display Pro calibrator.
The i1 software is asking me whether the technology used is CCFL (Cold-Cathode Fluorescent), Wide-Gamut CCFL, White LED or RGB LED.
From other threads, I'm pretty sure it's LED backlighting technology as the screen lights up immediately at start-up, unlike CCFL which apparently starts dimmer before brightening. So I've calibrated it twice entering once 'RGB LED' and once 'White LED' to see the difference. The 'RGB LED' calibration makes the greys look slightly cyan, and the 'White LED' makes the greys look pretty neutral, if not slightly red, but I'm still unsure which technology is used.
It would be very helpful is someone knew the answer and could help me out. Many thanks!!

Answer 1

Open a terminal window and enter the following:
ioreg -lw0 | grep IODisplayEDID | sed "/[^<]*</s///" | xxd -p -r | strings -6
So on my 21.5 inch iMac I get this:
Pandora:~ frank$ ioreg -lw0 | grep IODisplayEDID | sed "/[^<]*</s///" | xxd -p -r | strings -6
LM215WF3-SLA1
Color LCD
Pandora:~ frank$
Google the model number and you'll get the manufacturers data sheet (as well as tons of other info).  For this iMac part of the spec sheet is:
regards
Message was edited by: Frank Caggiano - So you can see the Lamp Type: WLED white LED