Hi, I observed something very similar this after a jessie -> stretch dist-upgrade. My whole failing logfile is attached, and the gist of the problem was in these errors:
[...] [ 5115.028] (EE) systemd-logind: failed to get session: PID 4398 does not belong to any known session [...] [ 5116.097] (EE) modeset(0): drmSetMaster failed: Permission denied [ 5116.097] (EE) [ 5116.097] (EE) AddScreen/ScreenInit failed for driver 0 [...] The first error appeared to be the root cause - it was caused by not reading through https://www.debian.org/releases/stable/amd64/release-notes/ch-whats-new.en.html#x-no-longer-requires-root where it said that the new way needs libpam-systemd Nothing had installed that package in my dist-upgrade, probably because I didn't choose to observe Recommends. After installing that and rebooting, everything was fine and Xorg runs as my own user, yay. I'll also note here that my first searches for the latter error message had produced a workaround - installing xserver-xorg-legacy and setting needs_root_rights=yes in Xwrapper.config. But that result is obviously inferior. It would be much better if the Xorg modesetting error messages were somewhat clearer as to what actually went wrong. It looks like the defaults excluded the intel driver as such: [ 5115.616] (==) Matched nouveau as autoconfigured driver 0 [ 5115.616] (==) Matched nv as autoconfigured driver 1 [ 5115.616] (==) Matched modesetting as autoconfigured driver 2 [ 5115.616] (==) Matched fbdev as autoconfigured driver 3 [ 5115.616] (==) Matched vesa as autoconfigured driver 4 When it worked, driver 2 actually seems to have reported: [ 20.775] (II) modeset(0): [DRI2] Setup complete [ 20.775] (II) modeset(0): [DRI2] DRI driver: i965 [ 20.775] (II) modeset(0): [DRI2] VDPAU driver: i965 This is counterintuitive given that I have xserver-xorg-video-intel installed. If the intel driver is installed, that should provide at least some sort of a hint to the Xorg server on runtime. Maybe to include it in the list of defaults? I don't have several of the above drivers installed and these particular wrong defaults merely lead to more redundant error output... If not that, then perhaps the modesetting driver should tell the user that it tried to take command over these drivers, but that perhaps its failure should not be completely fatal? Arguably the situation is made complex by the fact that these laptops have two GPUs, the Intel and the Nvidia one, and so both the users and the software are more likely to be confused by default. -- 2. That which causes joy or happiness.
Xorg.0.log.old
Description: application/trash