[lubuntu-devel] "TTY" goes to black screen, then doesn't come out of it?

Tue Jan 28 17:57:16 UTC 2020

Walter:

Took a few minutes to try to look into the Nvidia side of things today when
I found my Gecko install to "go to a black screen" instead of a TTY, but at
least there I can F7 back out of it.  In trying a googly search I saw a
familiar looking title, something like, "Nvidia driver fails to enter TTY"
. . .  so I clicked on it, went to their "devtalk" section and there from
roughly 9/19 was a thread I started when I found the problem . . . only a
few months ago, but . . . "lost" in repressed memory zone.

I had filed a "bug.sh file"??? and looking at it their admin guy basically
said, "Looks like a problem with Mac's UEFI implementation, and we aren't
going to go back a fix problems with 'legacy hardware' . . . I've filed a
bug 2709067 on it, but don't expect anything to happen . . . ."

I tried to search their site with that bug and google, but looks like it is
an "internalized" bug system . . . ??  So, point being, this isn't a "new"
issue, it was just held down and repressed, and then it boomeranged back
recently seemingly as a "new" problem . . . but, it's not new and doesn't
look like Nvidia is wasting any time on it.

I've got my two ubuntu installs set back to nouveau . . . I went over to
proprietary because of problems I mentioned in my Nvidia thread where
"resume from suspend" wasn't working in nouveau . . . went to nvidia . . .
which then provided resume from suspend, but . . . no TTY . . . .

That's the latest on it . . . prolly no point in messing with it here on
this list . . . if I do find that rolling back in the Nvidia drivers I
might post it back here . . . otherwise, we can guess that Nvidia isn't
messing with a GTX 780 that has issues in linux operation.

On Sun, Jan 26, 2020 at 9:49 AM Fritz Hudnut <este.el.paz at gmail.com> wrote:

> Walter:
>
> Thanks for the data . . . seems like in the case of Lu on my computer it
> is F1 that returns the GUI . . . hilarious.
>
> F
>
> On Sat, Jan 25, 2020 at 11:36 PM Walter Lapchynski <wxl at ubuntu.com> wrote:
>
>> On Sat, Jan 25, 2020 at 03:06:28PM -0800, Fritz Hudnut wrote:
>> > I was going to boot Lu 20.04…but for some reason the
>> > computer booted U-MATE 20.04
>>
>> Oh, these computers and their capricious ways… 😉
>>
>> > I guess the only one I didn't try was F1???
>>
>> "You never know until you find out"
>>      [Ned's Atomic Dustbin][1]
>>
>> Incidentially, I have seen cases where the key to return to the GUI was
>> F7 and cases where it was F1, across different Ubuntu flavors.
>>
>> It's always true that the number of active ttys is six, as you
>> can see with `grep tty /etc/default/console-setup`. You can also see
>> this in `systemd` with `grep NAutoVTs /etc/systemd/logind.conf`. An
>> interesting thing about at least current systemd is that ttys are
>> created on-demand thus the reason for "Auto" in that key.
>>
>> The kernel gives a lot more (`ls -h /dev/tty[1-9]* | wc -l` says 63) but
>> only the ttys that have getty running on them are accessible as
>> virtual terminals. X runs on a tty that doesn't have getty running.
>> You can see what's going on with something like
>>
>>     for t in {1..7}; do ps --no-headers --tty /dev/tty$t; done
>>
>> That said, all twelve function keys are defined with control and alt to
>> switch between the different ttys (aka consoles, virtual terminals),
>> which you can see with the likes of
>>
>>     dumpkeys | grep \
>>     "^[[:space:]]*control[[:space:]]*alt[[:space:]]*keycode.*Console_"
>>
>> Actually, if you just do `dumpkeys | grep Console` you'll find there are
>> a whole plethora of shortcuts for switching between the terminals.
>>
>> The only question remaining is why does X end up on tty7 sometimes and
>> other times not? Actually, I think this is circumstantial. Lubuntu
>> 18.04 and previous, like Ubuntu MATE and Ubuntu proper and every other
>> flavor of Ubuntu except for Kubuntu, all used lightdm for their display
>> manager. Kubuntu has long used sddm, and so has Lubuntu since after
>> 18.04. Incidentially, the two display managers have different feelings
>> about what tty to use.
>>
>> In lightdm's case, [they've had it set to 7 for 9 years][2], ever since
>> they first added support for users to define the specific tty you want
>> to use. This is changed to use 1 simply by editing
>> /etc/lightdm/lightdm.conf (you will likely have to create it) as such
>> and then restarting the display manager
>>
>>     [LightDM]
>>     minimum-vt=1
>>
>> In regards to sddm, [when they added support for a specific tty][3],
>> they set the default as 7. However, when systemd came around, they
>> [conditionally set it to 1 or 7][4] with the former being preferred in
>> the case of systemd. Why that is, I don't know, but it's easily changed
>> as above, except in this case, with /etc/sddm.conf, to 7 with
>>
>>     [X11]
>>     MinimumVT=7
>>
>> So, ok, maybe some things are a bit different. But not really.
>>
>> [1]: https://www.youtube.com/watch?v=LlMB9svNRzo
>> [2]:
>>
>> https://github.com/canonical/lightdm/commit/5372aa1c34db925fabae586e6003d58908e9e307
>> [3]:
>>
>> https://github.com/sddm/sddm/commit/af8d253d119104ec37059f8920aceae6b204b307
>> [4]:
>>
>> https://github.com/sddm/sddm/commit/3f9c18b5129a7110c5974036feb8b210f46ffc4a
>>
>> --
>>        @wxl | polka.bike
>> C563 CAC5 8BE1 2F22 A49D
>> 68F6 8B57 A48B C4F2 051A
>>
>
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