Commit 96b02f2f authored by Randy Dunlap's avatar Randy Dunlap Committed by Petr Mladek
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Docs: printk: add 'console=null|""' to admin/kernel-parameters 



Tell about 'console=null|""' and how to use it.

It can be helpful to set (enable) CONFIG_NULL_TTY so that the ttynull
driver is available. This avoids problems with stdin/stdout/stderr of
the init process. Howevere, CONFIG_NULL_TTY cannot be enabled by default
because it can be used by mistake, see the commit a91bd622 ("Revert
"init/console: Use ttynull as a fallback when there is no console"").

Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
[pmladek@suse.com: Slightly update wording.]
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220216203745.980-1-rdunlap@infradead.org
parent 2ba3673d

Documentation/admin-guide/kernel-parameters.txt

+6 −0
Original line number Diff line number Diff line
@@ -724,6 +724,12 @@ 
		hvc<n>	Use the hypervisor console device <n>. This is for

			both Xen and PowerPC hypervisors.



		{ null | "" }

			Use to disable console output, i.e., to have kernel

			console messages discarded.

			This must be the only console= parameter used on the

			kernel command line.



		If the device connected to the port is not a TTY but a braille

		device, prepend "brl," before the device type, for instance

			console=brl,ttyS0