We upgraded to Ubuntu 22.04 from 16.04 sometime ago, ever since upgrading, I noticed a peculiar issue. Our syslog is completely spammed every second or so, by gdm-x-session with the following repeating entries:
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): EDID vendor "PHL", prod id 49343
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): DDCModeFromDetailedTiming: 720x480 Warning: We only handle separate sync.
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Using hsync ranges from config file
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Using vrefresh ranges from config file
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Printing DDC gathered Modelines:
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "1600x900"x0.0 108.00 1600 1624 1704 1800 900 901 904 1000 +hsync +vsync (60.0 kHz eP)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "720x480"x0.0 27.00 720 736 798 858 480 489 495 525 -hsync -vsync (31.5 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "1920x1080"x0.0 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync (67.5 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "1280x720"x0.0 74.25 1280 1390 1430 1650 720 725 730 750 +hsync +vsync (45.0 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "800x600"x0.0 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "640x480"x0.0 31.50 640 656 720 840 480 481 484 500 -hsync -vsync (37.5 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "640x480"x0.0 31.50 640 664 704 832 480 489 492 520 -hsync -vsync (37.9 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "640x480"x0.0 30.24 640 704 768 864 480 483 486 525 -hsync -vsync (35.0 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "640x480"x0.0 25.18 640 656 752 800 480 490 492 525 -hsync -vsync (31.5 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "720x400"x0.0 28.32 720 738 846 900 400 412 414 449 -hsync +vsync (31.5 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "1280x1024"x0.0 135.00 1280 1296 1440 1688 1024 1025 1028 1066 +hsync +vsync (80.0 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "1024x768"x0.0 78.75 1024 1040 1136 1312 768 769 772 800 +hsync +vsync (60.0 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "1024x768"x0.0 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync (48.4 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "800x600"x0.0 49.50 800 816 896 1056 600 601 604 625 +hsync +vsync (46.9 kHz e)
/usr/libexec/gdm-x-session[1030]: (II) modeset(0): Modeline "1280x1024"x0.0 108.00 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync (64.0 kHz e)
/usr/libexec/gdm-x-session[1030]: (--) modeset(0): HDMI max TMDS frequency 225000KHz
I couldn't find much information about this online. I have found several users, with similar issues
Any help is greatly appreciated
Update/edit1:
After some more research, I discovered that gdm-x-session is just a "wrapper" around Xorg.
In my case, gdm-x-session launches Xorg with the following arguments
(Copied from /proc/#/cmdline)
/usr/lib/xorg/Xorg vt2 -displayfd3 -auth /run/user/1000/gdm/Xauthority -nolistentcp -backgroundnone -noreset -keeptty -novtswitch -verbose 3
Specifically -verbose 3 seems interesting, however I cannot find how to set log-verbosity from gdm-x-session
Update/edit2:
I discovered that you can filter certain messages from being output to syslog.
Since gdm-x-session info-logs, usually start with "(II) modeset(0):"
I created the following filter in /etc/rsyslog.d/10-gdm-x-session-filter.conf
:msg, contains, "(II) modeset(0):" stop
This will discard any log entry with the string "(II) modeset(0):" (I couldn't get programname to work, for some reason).
The issue is somewhat "solved", but gdm-x-session still outputs device-info logs every second to ~/.local/share/xorg/Xorg.0.log
