Bug#909770: gdm3: Does not show the list of users and fails to start any session

[Simon McVittie]

On Fri, 28 Sep 2018 at 11:01:09 +0200, Sergio Villar Senin wrote:
> O Xov, 27-09-2018 ás 22:39 +0100, Simon McVittie escribiu:
> > On Thu, 27 Sep 2018 at 23:16:05 +0200, Sergio Villar Senin wrote:
> > >    The background of the plyumouth theme is shown but the list of
> > >    users is not there as expected.

How many screens are you using, and how are they connected?  From your
log it looks as though the answer might be one laptop internal panel,
connected via eDP, and no external screens. Is that correct?

If you are using a plymouth theme that resembles the background you would
expect for the gdm greeter (user list), please retry with a different
plymouth theme such as softwave or lines and tell me what you see? (What
I'm trying to determine here is whether the most recent pixels on your
screen came from plymouth or gdm.)

> I don't see anything specially wrong there except these lines:
> 
> laptop kernel: [drm:intel_dp_start_link_train [i915]] *ERROR*
> [CONNECTOR:71:eDP-1] Link Training failed at link rate = 270000, lane
> count = 2

I agree. This looks more like a kernel bug than anything else - I'm not
sure that this is anything that gdm3 can fix - but I'll try to get a
bit more information about what does and doesn't work before reassigning.

If you follow the workaround that you described (involving suspend/resume),
do you get a similar warning about link training after resuming?

You said that lightdm works OK. Do you get similar warnings about link
training when using lightdm?

If you edit /etc/gdm3/daemon.conf and edit it to have

    [daemon]
    WaylandEnable=false

then go back to gdm, does that make it work?

    smcv