[argyllcms] Re: nVidia Optimus External Monitor Calibration and Profiling
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Mon, 13 Oct 2014 16:54:02 +1100
Leonardo Facchin wrote:
Hi,
> The laptop graphics system makes use of the nVidia Optimus technology.
Beware - it's been reported that igfxpers.exe that gets installed with nVidia
"Optimus"
technology interferes with Video LUT loading. I'm told that you may have to
disable both
the igfx tray module (c:\windows\system32\igfxtray.exe) and the igfxpph Module
(c:\windows\system32\igfxpph.dll) in addition to the persistence Module
(c:\windows\system32\igfxpers.exe). I have no idea what effect that has on the
system
operation though.
If nVidia have fixed these problems it would be good to know, so that I
can update the documentation.
> The problem is that right now I'm totally lost and confused about how the
> "two" graphics
> cards actually interact with the calibration and profiling process. Let's
> assume that I
> could force both the relevant Adobe softwares to run with the nVidia GPU
> (which I did) and
> the Argyll CMS components to do the same (which I didn't: even if I associate
> the Argyll
> executables to the nVidia GPU, when I run them the GPU remains idle, at least
> according to
> the nVidia Optimus GPU State Viewer, a little software meant to show when the
> GPU is
> powered up and running).
ArgyllCMS doesn't use the GPU, so I wouldn't expect an association to do
anything.
> Still, how can I know how many LUTs the system can access and which graphics
> card control
> each of them? Could the two cards be sharing the LUTs? Does it even make
> sense?
The Video LUT is logically associated with a Video output port, so if it's been
implemented correctly, there should be only a single set of LUTs, probably in
the
Intel hardware if it's driving the HDMI port, but in any case there is only
a single operating system API per display. Now, they may messed all that
up (hence the feedback that igfxpers.exe is a problem.)
> I know that the easiest solutions would probably be to stick to the
> Integrated Processing
> Unit and be done with it, but on the one hand the total confusion is
> undermining my trust
> in the accuracy of my color managed workflow and on the other I just
> developed the
> curiosity to understand a little better how this system works.
It's usually not that hard to figure out what's going on. Use dispwin -c to
clear the VideoLUTs, and dispwin strange.cal to set a noticeable LUT. That
will tell you whether calibration loading is working as expected.
<http://www.argyllcms.com/doc/dispwin.html>
Graeme Gill.
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