Bug 180493 - [handbook] Single-user mode console confusion
Summary: [handbook] Single-user mode console confusion
Status: Open
Alias: None
Product: Documentation
Classification: Unclassified
Component: Documentation (show other bugs)
Version: Latest
Hardware: Any Any
: Normal Affects Only Me
Assignee: freebsd-doc mailing list
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-07-12 15:30 UTC by ahamiltonwright
Modified: 2017-12-31 22:27 UTC (History)
0 users

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Description ahamiltonwright 2013-07-12 15:30:00 UTC
I have these lines in /boot/loader.conf in order to enable a sometimes-installed serial console device:

boot_multicons="YES"
boot_serial="YES"
comconsole_speed="19200"
console="comconsole,vidconsole"


A side effect of these lines is that entering single-user mode produces a prompt only on the external console.  This was extremely confusing when attempting to boot single-user, as all messages prior to the single-user prompt are produced on the vid terminal (and on the external console), however at the moment that single-user mode is entered, the mirroring ceases.  While it is now clear what happened, the effect is that single-user mode appears to be unavailable.

I have no /boot.config file that would indicate which console is meant to be used for messages.

Fix: 

I would suggest adding some text to the handbook page "Setting up the Serial Console"
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/serialconsole-setup.html#serialconsole-loader

Currently, these page makes no comment regarding single-user mode whatsoever.  Informing the user that configuring the console may well have repercussions on entry to single-user mode will lessen confusion in the future.


 I would therefore suggest adding the following text into section 26.6.6 "Setting up the Console from the Boot Loader", subsection 26.6.6.1 "Setting Up the Serial Console":


Note that entry to single-user mode will only honour input on one console, even if multiple consoles are indicated using the <tt>console</tt> boot option.  Care must be taken that the first named console is available to the system manager entering single-user mode.


I will note that the first sentence in this section "The boot loader and the kernel to use the serial console can be specified by writing one line in /boot/loader.conf" seems very poorly written -- I do not understand what this line is attempting to say.



Additionally, there is already a section "26.6.7 Caveats"; a note here indicating possible effects on single-user boot would probably not go amiss.
How-To-Repeat: Add these lines to /boot/loader.conf, attempt to boot single user.
Comment 1 Eitan Adler freebsd_committer freebsd_triage 2017-12-31 08:00:55 UTC
For bugs matching the following criteria:

Status: In Progress Changed: (is less than) 2014-06-01

Reset to default assignee and clear in-progress tags.

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