Re: 10-but LUTs and the Dell U2711

[Richard Hughes <hughsient gmail com>]

On 20 July 2010 20:06, Andrew Lutomirski <luto mit edu> wrote:
> I have a Dell U2711, which has 10 bits per channel over DisplayPort
> (although I'm not sure that anything other than i915 can drive 10 bits
> right now, and even i915 needs bleeding-edge drivers).  Can GCM
> program a 10-bit video card LUT?

In theory, yes. I've made the GcmClut object generate the amount of
data for each LUT size, but I admit I've never tested it on anything
other than 8 bpp.

> Also, the U2711 has an internal LUT, although no one seems to know how
> to program it (even on Windows) or even whether it can be programmed
> with anything other than a (not-very-good) factory calibration.
> Richard, did your libcolor-glib work give you any ideas for how to
> test for DDC control of a LUT on an unknown monitor?  I'd be happy to
> test and fiddle.

Yes. I'm still waiting for me DreamColor monitor to arrive, and that
allows a custom colorspace to be uploaded. For your monitor, you
probably need to convince the manufacturer to give you the specs, or
find a windows tool that calibrates the monitor and then trace that.

You always have to be a little but careful sending hardware random
data to reverse engineer it. First, the output of "gcm-ddc-util
--enumerate" should give us something to work on.

Richard.