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Re: Jessie for Udoo X86?




On Thu, Apr 20, 2017 at 07:11:53AM -0700, Larry Dighera wrote:
> I'm familiar with the dmesg output at boot time.  I see that when I choose
> to boot into recovery mode from the grub menus.  When the scrolling text
> stops, I'm left with what I thought was a frozen screen, but it turns out to
> be login, without a prompt, waiting for me to provide the root password.
> Once I submit the root password, I have a command line interface to a
> reasonably functional Debian system.

Debian's GRUB menu passes a "quiet" parameter[1] to the kernel to
suppress most of the normal messages.  If this parameter is omitted
(e.g. when you use the "Recovery mode" choice in GRUB), you get kernel
messages from various subsystems as they are brought up.

Before systemd, booting was a much more linear process.  Subsystems
would be brought up one by one, and when enough of them were ready,
you'd get a login prompt.

Now, however, the highly parallelized systemd boot means multiple
subsystems are being brought up simultaneously, and some of them are
still initializing when the login prompt is displayed.  If you're also
seeing their output, what this means is *sometimes*, depending on how
the race conditions play out, you might get system output *after* the login
prompt has already been displayed.  If you aren't carefully reading
everything on the screen, it may be easy to overlook the login prompt
buried several lines up (or in a very bad case scenario, even scrolled
off the visible terminal).

Normally, once things seem like they've reached a stable point, if you
aren't sure if there's a login prompt, it should be safe for you to
press Enter.  If you're seeing a regular getty login prompt, then
you should simply get another one.  If you're getting the single user
mode "enter root password to continue" prompt, you should get another
one of those as it considers your blank password to be a failed login
attempt, and it shouldn't self-destruct or anything like that after
just one failed attempt.

[1] See GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub.