On 18 May 2014 15:24, Sanford Rockowitz <rockow...@minsoft.com> wrote: > I apologize in advance for posting a question about DDC/CI to this list, > as it's not quite on topic. People here have been very helpful and I'd > certainly appreciate suggestions as to a more appropriate place to post.
This would be interesting to the people using colord too, so I've included a CC. > When I perform a calibration, it's specific to the current settings of > the monitor: color temperature, RGB channel settings, brightness, etc. Right. Some hardware can't do any of this, e.g. laptops, although in theory we can know this from the DDC data. > Yet handling these settings is an out of band process. It's the user's > responsibility to manually adjust the monitor settings and record the > values before calibration, and restore them manually if necessary. At > the very least, it would be desirable to record those settings in the > profile, or even just have a utility that allowed me to record the > settings and possibly restore them. At the moment GNOME, XFCE and KDE automatically set the backlight brightness to the value used for profiling on session start, although the user is free to change it as they wish. > Googling, I find a bunch of posts from Kae-Uwe Berman, Graeme Gill, > Richard Hughes and others circa 2009-2010 (e.g. > http://comments.gmane.org/gmane.comp.freedesktop.xorg/41559, > http://lists.x.org/archives/xorg-devel/2010-July/010922.html) Then > discussion of this topic seems to die. There are several good reasons for this, the biggest being that DDC/CI is underspecified and also wrongly implemented by a *lot* of vendors. For instance, on my high-end HP DreamColor monitor the DDC/CI API behaves as you would expect, with a few HP specific extensions. When you call GetContrast, you get the contrast value. The *huge* problem with DDC/CI is that it's not really used by Windows to the full extent, and if nothing is using it by default, you get firmware engineers doing crazy things. IIRC, on my LG monitor the "Contrast" scale is inverted. On my el-cheapo Sony rebranded panel using DDC/CI anything more than getting the EDID sometimes triggers the panel to reset to the factory defaults. I've heard other people report that setting the brightness on some old CRT monitors did crazy things like a degaussing. This is why the ddccontrol project has that huge unmaintained XML file of all the monitor quirks for basically every monitor. I'd love to say that in 2014 monitors are just doing the right thing and that quirks are no longer required, but you've found out the hard way that's not true :) I do see some value in recording things like the "contrast" in the ICC file, and restoring it at session start if set, but it's not the kind of thing we can support by default as the hardware support just isn't there. Maybe a whitelist might work. Ideas welcome. Richard. ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
