where does gnome-display-properties save the different configurations?

Question

I use gnome-display-properties to configure the external screens that I attach to my laptop at home and in the office. Gnome-display-properties cleverly remembers which screen is which, and automatically sets the display up when the screen is plugged.

For example, in gnome-display-properties, the monitor shows as "Monitor: Samsung Electric Company 24''", I wonder where is this info pulled from?

Where is this information saved?

Answer 1

The information is coming from the monitor's EDID. To check, you can install the package read-edid and run

sudo get-edid | parse-edid

That should output some info including the monitor section we previously had in our xorg.conf files, e.g.:

Section "Monitor"
    # Block type: 2:0 3:ff
    # Block type: 2:0 3:fc
    Identifier "DELL U2311H"
    VendorName "DEL"
    ModelName "DELL U2311H"
    # Block type: 2:0 3:ff
    # Block type: 2:0 3:fc
    # Block type: 2:0 3:fd
    HorizSync 30-83
    VertRefresh 56-76
    # Max dot clock (video bandwidth) 170 MHz
    # DPMS capabilities: Active off:yes  Suspend:yes  Standby:yes

    Mode    "1920x1080" # vfreq 60.000Hz, hfreq 67.500kHz
        DotClock    148.500000
        HTimings    1920 2008 2052 2200
        VTimings    1080 1084 1089 1125
        Flags   "+HSync" "+VSync"
    EndMode
    # Block type: 2:0 3:ff
    # Block type: 2:0 3:fc
    # Block type: 2:0 3:fd
EndSection

Note the three letter VendorName.

Answer 2

Adding to htorque's answer and converting JohanSJA's comment to an answer:

Where is this information saved?

In ~/.config/monitors.xml.