This is not a bug, but a feature request.
In GNOME, or with ArgyllCMS, one can calibrate or profile the monitor once, disconnect the colorimeter, and the generated profile will be used with the monitor (both for loading LUT tables into the video adapter and for the actual color correction) until changed explicitly. This makes sense, but this is not how Windows drivers for ColorMunki Display suggest to work.
Instead, they suggest that you leave your colorimeter connected, cover the lens with the included light diffusor, and place it on your desk. The driver then will periodically measure the ambient light intensity and its color temperature, and dynamically change the monitor brightness via DDC-CI or update the LUT contents or even update the color profile itself.
The explanation is that you want the images displayed on your monitor and printed by your printer match. However, the printed image is affected by the color temperature of the ambient light, while the image on the monitor isn't. So there WILL be unwanted differences if you profiled the monitor at 12:00 when the light comes through the window, but also want to use it at 19:00 when it is dark in the street and ceiling lights are on in the office.
Also (not sure if it is a colord task at all), a Sony VAIO Z23A4R laptop comes with an integrated ambient light sensor that the integrated Windows software also uses to autoadjust the LCD brightness.
Why not do the same in GNOME?
(In reply to comment #0)
> Also (not sure if it is a colord task at all), a Sony VAIO Z23A4R laptop
> comes with an integrated ambient light sensor that the integrated Windows
> software also uses to autoadjust the LCD brightness.
I tried to use the ambient sensor a long time ago in gnome-power-manager and it was a disaster from a usability point of view. I don't think we want to support re-loadable vcgt's in profiles, so I think this is probably out of scope for colord, sorry.