On 13 Mar 2003, Ben Guthro wrote: > Xinerama aside, even in a dual head system running without Xinerama, I > am having a difficult time retrieving the XFree86_DDC_EDID1_RAWDATA for > the second (non-primary) screen > > xlsatoms |grep EDID > yields > 69 XFree86_DDC_EDID1_RAWDATA > 209 XFree86_DDC_EDID1_RAWDATA > 489 XFree86_DDC_EDID2_RAWDATA > > however when running > xprop -root |grep EDID > on the second screen, it yields no results, and running it on the first > screen prints one atom. > > so...what window are those other two attached to so I can retrieve that > information with XGetWindowProperty?
Wow, I'd forgotten all about that. In your case xprop -root on the first screen prints the data in atom 209. Atom 69 is a hack; because the EDID data is found before the screen is created, there isn't yet a root window to attach it to. Instead we create a screenless atom (69), then copy it when we create the screen (in xf86Init.c xf86CreateRootWindow() ). XFree86_DDC_EDID2_RAWDATA isn't the data for the second screen. It is used when the monitor returns data in a EDID v2 data structure (256 bytes as opposed to 128). I've never seen a monitor which returns that. There are however monitors which return 128 bytes, but report that they are version 2, since they return it in the structure described in version 2 of the EDID standard (this is really EDID v1.1). We detect this case by the EDID checksum, and create both properties. grepping for EDID in the log file should alert you to that case. Other than that I've never seen an XFree86_DDC_EDID2_RAWDATA property, so would be interested to see your log file. I have more machines than monitors, so haven't looked very hard at the dual head case, and wouldn't be suprised if there are cases where the second head EDID data is wrong or not made available. -- Dr. Andrew C. Aitchison Computer Officer, DPMMS, Cambridge [EMAIL PROTECTED] http://www.dpmms.cam.ac.uk/~werdna _______________________________________________ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
