Hi, I am working on updating a 5 year old debian installation on a T510 thinkpad for my sister-in-law and after wasting about ten hours I am a bit out of ideas... First I started the slow path upgrading debian 8 to 9 and then 10, but 10 completely broke the nvidia setup for the NVIDIA Corporation GT218M [NVS 3100M] X interface. I could not get the nvidia-legacy-340xx-driver to work, and nouveau did not cover it either. So I then changed over to direct debian 11 (bullseye) install. The live usb system worked fine after adding the wlan firmware, but after finishing the installation neither network (cable or wlan) nor X windows worked. slim hangs waiting for x to startup and it completely blocks off the keyboard so I can't even switch virtual terminal to a console. So the next step was to try chimaera. At least the network works normally so I get in via ssh, but the X installation is also broken, both debian and devuan show the same entries in Xorg.0.log, both with or without setting up xorg.con explicitly with X -configure

Without xorg.conf:
[  1531.149] (II) Loading sub module "glamoregl"
[  1531.149] (II) LoadModule: "glamoregl"
[  1531.149] (II) Loading /usr/lib/xorg/modules/libglamoregl.so
[  1531.149] (EE) Failed to load /usr/lib/xorg/modules/libglamoregl.so: libffi.so.6: cannot open shared object file: No such file or directory
[  1531.149] (EE) modeset: Failed to load module "glamoregl" (loader failed, 0)
[  1531.149] (EE) modeset(0): Failed to load glamor module.

and

[  1531.823] (II) LoadModule: "libinput"
[  1531.823] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[  1531.824] (EE) Failed to load /usr/lib/xorg/modules/input/libinput_drv.so: /usr/local/lib/libinput.so.10: version `LIBINPUT_1.15' not found (required by /usr/lib/xorg/modules/input/libinput_drv.so)
[  1531.824] (EE) Failed to load module "libinput" (loader failed, 0)
[  1531.824] (EE) No input driver matching `libinput'
[  1531.824] (II) Falling back to input driver `libinput'
[  1531.824] (II) LoadModule: "libinput"
[  1531.824] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[  1531.824] (EE) Failed to load /usr/lib/xorg/modules/input/libinput_drv.so: /usr/local/lib/libinput.so.10: version `LIBINPUT_1.15' not found (required by /usr/lib/xorg/modules/input/libinput_drv.so)
[  1531.824] (EE) Failed to load module "libinput" (loader failed, 0)
[  1531.824] (II) config/udev: Adding input device SynPS/2 Synaptics TouchPad (/dev/input/event2)
[  1531.824] (**) SynPS/2 Synaptics TouchPad: Applying InputClass "libinput touchpad catchall"
[  1531.824] (II) LoadModule: "libinput"
[  1531.824] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[  1531.825] (EE) Failed to load /usr/lib/xorg/modules/input/libinput_drv.so: /usr/local/lib/libinput.so.10: version `LIBINPUT_1.15' not found (required by /usr/lib/xorg/modules/input/libinput_drv.so)
[  1531.825] (EE) Failed to load module "libinput" (loader failed, 0)
[  1531.825] (EE) No input driver matching `libinput'
[  1531.825] (II) Falling back to input driver `libinput'
[  1531.825] (II) LoadModule: "libinput"

With xorg.conf the nouveau server starts:
[   613.133] (EE) Failed to load /usr/lib/xorg/modules/input/libinput_drv.so: /usr/local/lib/libinput.so.10: version `LIBINPUT_1.15' not found (required by /usr/lib/xorg/modules/input/libinput_drv.so)
[   613.133] (EE) Failed to load module "libinput" (loader failed, 0)
[   613.133] (EE) No input driver matching `libinput'
[   613.133] (II) Falling back to input driver `libinput'
[   613.133] (II) LoadModule: "libinput"
[   613.133] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[   613.133] (EE) Failed to load /usr/lib/xorg/modules/input/libinput_drv.so: /usr/local/lib/libinput.so.10: version `LIBINPUT_1.15' not found (required by /usr/lib/xorg/modules/input/libinput_drv.so)
[   613.133] (EE) Failed to load module "libinput" (loader failed, 0)
[   613.134] (II) config/udev: Adding input device Video Bus (/dev/input/event1)
[   613.134] (**) Video Bus: Applying InputClass "libinput keyboard catchall"
[   613.134] (II) LoadModule: "libinput"
[   613.134] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[   613.134] (EE) Failed to load /usr/lib/xorg/modules/input/libinput_drv.so: /usr/local/lib/libinput.so.10: version `LIBINPUT_1.15' not found (required by /usr/lib/xorg/modules/input/libinput_drv.so)
[   613.134] (EE) Failed to load module "libinput" (loader failed, 0)
[   613.134] (EE) No input driver matching `libinput'
[   613.134] (II) Falling back to input driver `libinput'
[   613.134] (II) LoadModule: "libinput"
[   613.134] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[   613.135] (EE) Failed to load /usr/lib/xorg/modules/input/libinput_drv.so: /usr/local/lib/libinput.so.10: version `LIBINPUT_1.15' not found (required by /usr/lib/xorg/modules/input/libinput_drv.so)
[   613.135] (EE) Failed to load module "libinput" (loader failed, 0)

It looks like bullseye/chimaera have libinput version 1.16 and not 1.15. I am scratching my head here, because on a modern ThinkStation chimaera installed without any difficulties, so I suspect it is not that the whole dependencies for the xserver were basically completely broken in stable. Any ideas?

Found it... I had to preserve /home, /opt and /usr/local, and /usr/local/lib was in LD_LIBRARY_PATH and superseded the default libraries. Well, so my sister-in-law will now get chimaera instead of bullseye....