[argyllcms] Re: argyllcms Digest V9 #99
- From: Elle Stone <l.elle.stone@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Mon, 7 May 2012 09:31:26 -0400
On 5/5/12, Kai-Uwe Behrmann <ku.b@xxxxxx> wrote:
> Date: Fri, 4 May 2012 09:46:32 -0400 Subject: [argyllcms] Re: Mystery
> monitor profile installed itself From: Elle Stone
> <l.elle.stone@xxxxxxxxx> On 5/4/12, Kai-Uwe Behrmann <ku.b@xxxxxx> wrote:
> > What I still can't figure out is where that weird vcgt stuff is coming
> > from. It's easy enough to replace it: just add "dispwin -c" to the
> > .xinitrc file. And it isn't coming from the Oyranos-generated monitor
> > profile. So what's generating it?
>
> You might try twm, which is a pretty simple WM and see if that helps
> locating the origin. XDG knows a about some start script folders which
> might jump in automatically unnoticed. /etc/xdg/autostart and others. (I
> am not on linux to name exact locations.)
>
> kind regards
> Kai-Uwe
>
Thanks very much for trying to help locate how/where/when the odd vcgt
is being loaded.
All three of our linux computers exhibit the same behavior, regardless
of the type of installation. The only thing in my autostart folder on
my Debian Sid installation is, well, nothing, as there is no autostart
folder. It's a barebones minimal command line installation.
If I use "dispwin -c" to clear the vcgt information,
and then check with "dispwin -s cleared.cal", "cleared.cal" reads (in
part) as follows:
NUMBER_OF_SETS 256
BEGIN_DATA
0.0000 0.0000 0.0000 0.0000
3.9216e-03 3.9216e-03 3.9216e-03 3.9216e-03
7.8431e-03 7.8431e-03 7.8431e-03 7.8431e-03
0.011765 0.011765 0.011765 0.011765
0.015686 0.015686 0.015686 0.015686
0.019608 0.019608 0.019608 0.019608
0.023529 0.023529 0.023529 0.023529
0.027451 0.027451 0.027451 0.027451
0.031373 0.031373 0.031373 0.031373
which is consistent with "nothing loaded" or linear calibration.
If I then run "xgamma -gamma 1.00" the screen output reads:
-> Red 1.000, Green 1.000, Blue 1.000
<- Red 1.000, Green 1.000, Blue 1.000
which also is consistent with linear calibration
However, upon running "dispwin -s after-xgamma.cal", the output looks like this:
NUMBER_OF_SETS 256
BEGIN_DATA
0.0000 0.0000 0.0000 0.0000
3.9216e-03 3.9063e-03 3.9063e-03 3.9063e-03
7.8431e-03 7.8126e-03 7.8126e-03 7.8126e-03
0.011765 0.011719 0.011719 0.011719
0.015686 0.015625 0.015625 0.015625
0.019608 0.019532 0.019532 0.019532
0.023529 0.023438 0.023438 0.023438
0.027451 0.027344 0.027344 0.027344
0.031373 0.031250 0.031250 0.031250
Which is exactly the odd vcgt that I was trying to track down.
According to http://linux.die.net/man/1/xgamma:
"The gamma values are passed to the Xserver with 3 decimal places of accuracy."
Like I said, it looks like a rounding error.
xgamma is probably not the culprit. xgamma is located in /usr/bin. It
is part of "x11-xserver-utils" and so would be difficult to uninstall.
However, as root, I renamed it to zzzxgamma, used "dispwin -c" to
clear the vcgt information, and restarted the computer. The same odd
vcgt information was still present, according to "dispwin -s
restart.cal".
Does anyone have a clue what really is loading this "almost linear
calibration but with rounding errors" vcgt information upon computer
startup?
According to Graeme's documentation, native monitor profiles make less
artifacting than profiling after calibration using vcgt tags to alter
the video card output. Is this odd "not quite cleared" vcgt
information likely to cause artifacting?
I expect that my three computers are not the only computers that are
loading this odd vcgt information upon startup. "dispwin -c" will
clear the information.
Warm regards,
Elle
--
Elle Stone
http://ninedegreesbelow.com
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