Re: X.org works on <= 14.3, unusable on >= 14.4

Den 2026-08-03 kl. 20:55, skrev Dag-Erling Smørgrav:
> I have a Lenovo ThinkVision with an Intel Core i7-10700T with integrated
> graphics and dual Lenovo ThinkVision monitors connected using DP.  This
> has been working beautifully for several years, up to and including
> 14.3, using i915kms and the modesetting driver (no xorg.conf).  Current
> package versions:
>
>      xorg-server-21.1.24,1
>      drm-61-kmod-6.1.128.1403000_10
>      gpu-firmware-intel-kmod-kabylake-20260519.1403000
>
> (no, I don't know why it's using Kaby Lake firmware on a Comet Lake CPU,
> I have all the flavors installed and this is the one it picks)
>
> Starting with 14.4, I can still start X but the display flickers on
> every update, which renders it unusable with anything even moderately
> graphics-intensive, including `tail -F /var/log/Xorg.0.log` in a
> terminal.  It appears that each time it flickers it also dumps EDID and
> modeline information about my monitors to the log:
>
>      [    67.784] (II) modeset(0): EDID vendor "LEN", prod id 25077
>      [    67.784] (II) modeset(0): Using EDID range info for horizontal sync
>      [    67.785] (II) modeset(0): Using EDID range info for vertical refresh
>      [    67.785] (II) modeset(0): Printing DDC gathered Modelines:
>      [    67.785] (II) modeset(0): Modeline "2560x1440"x0.0  241.50  2560 2608 2640 2720  1440 1443 1448 1481 +hsync -vsync (88.8 kHz eP)
>      [    67.785] (II) modeset(0): Modeline "1280x720"x0.0   74.25  1280 1390 1430 1650  720 725 730 750 +hsync +vsync (45.0 kHz e)
>      [    67.785] (II) modeset(0): Modeline "2560x1440"x0.0  299.00  2560 2608 2640 2720  1440 1443 1448 1470 +hsync -vsync (109.9 kHz e)
>      [    67.785] (II) modeset(0): Modeline "640x480"x0.0   25.18  640 656 752 800  480 490 492 525 -hsync -vsync (31.5 kHz e)
>      [    67.785] (II) modeset(0): Modeline "720x480"x0.0   27.00  720 736 798 858  480 489 495 525 -hsync -vsync (31.5 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1280x720"x0.0   74.25  1280 1720 1760 1980  720 725 730 750 +hsync +vsync (37.5 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1920x1080"x0.0  148.50  1920 2008 2052 2200  1080 1084 1089 1125 +hsync +vsync (67.5 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1920x1080"x0.0  148.50  1920 2448 2492 2640  1080 1084 1089 1125 +hsync +vsync (56.2 kHz e)
>      [    67.785] (II) modeset(0): Modeline "720x576"x0.0   27.00  720 732 796 864  576 581 586 625 -hsync -vsync (31.2 kHz e)
>      [    67.785] (II) modeset(0): Modeline "800x600"x0.0   40.00  800 840 968 1056  600 601 605 628 +hsync +vsync (37.9 kHz e)
>      [    67.785] (II) modeset(0): Modeline "640x480"x0.0   31.50  640 656 720 840  480 481 484 500 -hsync -vsync (37.5 kHz e)
>      [    67.785] (II) modeset(0): Modeline "640x480"x0.0   31.50  640 664 704 832  480 489 492 520 -hsync -vsync (37.9 kHz e)
>      [    67.785] (II) modeset(0): Modeline "640x480"x0.0   30.24  640 704 768 864  480 483 486 525 -hsync -vsync (35.0 kHz e)
>      [    67.785] (II) modeset(0): Modeline "720x400"x0.0   28.32  720 738 846 900  400 412 414 449 -hsync +vsync (31.5 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1280x1024"x0.0  135.00  1280 1296 1440 1688  1024 1025 1028 1066 +hsync +vsync (80.0 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1024x768"x0.0   78.75  1024 1040 1136 1312  768 769 772 800 +hsync +vsync (60.0 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1024x768"x0.0   75.00  1024 1048 1184 1328  768 771 777 806 -hsync -vsync (56.5 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1024x768"x0.0   65.00  1024 1048 1184 1344  768 771 777 806 -hsync -vsync (48.4 kHz e)
>      [    67.785] (II) modeset(0): Modeline "832x624"x0.0   57.28  832 864 928 1152  624 625 628 667 -hsync -vsync (49.7 kHz e)
>      [    67.785] (II) modeset(0): Modeline "800x600"x0.0   49.50  800 816 896 1056  600 601 604 625 +hsync +vsync (46.9 kHz e)
>      [    67.785] (II) modeset(0): Modeline "800x600"x0.0   50.00  800 856 976 1040  600 637 643 666 +hsync +vsync (48.1 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1280x1024"x0.0  108.00  1280 1328 1440 1688  1024 1025 1028 1066 +hsync +vsync (64.0 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1440x900"x0.0  106.50  1440 1520 1672 1904  900 903 909 934 -hsync +vsync (55.9 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1680x1050"x0.0  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync (65.3 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1920x1200"x0.0  193.25  1920 2056 2256 2592  1200 1203 1209 1245 -hsync +vsync (74.6 kHz e)
>      [    67.785] (II) modeset(0): Modeline "1152x864"x0.0  108.00  1152 1216 1344 1600  864 865 868 900 +hsync +vsync (67.5 kHz e)
>
> I tried playing with -logverbose but there is nothing else of any use in
> the log, just an endless repetition of the above EDID and modeline
> information.  Running the server with -logverbose 0 suppressed the log
> spam but did not cure the flickering or the slowdown.
>
> The monitors are currently daisy-chained using DisplayPort pass-through.
> Connecting the second monitor directly using HDMI instead made no
> difference.
>
> I have tried:
>
>   - 14.3 kernel, 14.3 world and packages - works
>   - 14.4 kernel, 14.3 world and packages - does not work
>   - 14.4 kernel, 14.4 world and packages - does not work
>   - 15.1 kernel, 15.1 world and packages - does not work
>
> Needless to say I'd like to get off 14.3 asap.
>
> Any ideas?
>
> DES

Hi,

Sorry for butting in. I have no idea what I'm talking about and I do not 
know if it will help you but I have an issue in 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=295788 for which I 
have found a workaround.

The symptoms are not exactly the same as yours but the workaround might 
be interesting anyway.


Try this:

Install the 14.4 and then use git to switch (while on the 14.4) to the 
14.3 kernel source tree. Then grab drm-515-kmod from the 2026Q2 ports 
tree, remove the version check in the Makefile for the drm-515-kmod, 
compile drm-515-kmod and try.

After the build you can switch back to kernel src for 14.4.


As I said, your symptoms are vastly different than mine so I'm most 
likely just wasting your time. Tuppence worth.

/Roger