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Xen HOWTO mention of the Xen console



The Xen HOWTO currently mentions "Xen's console" as follows:

	On Xen's console, one can type the escape character (default ^A)
	three times to switch input from Xen to the dom0.

That's kind of backwards because (so far as I know) there's really never
any opportunity, by default(*), to interact with Xen's console before it
switches the console input over to the dom0.  Note also it's a "switch"
character, not an "escape" character.

Perhaps the following text would be better (especially give that the Xen
console use is rather poorly documented anywhere else).

	On boot Xen switches the console input to the dom0 console just
	before it starts the dom0 kernel.  At any time after that point
	one can type the Xen console switch character three times (the
	default is <CTRL-A> (^A), which can be changed with the
	"conswitch=a" option on the Xen command line) to switch console
	input from the dom0 back to Xen (and then repeated to switch
	back to the dom0 again if desire).  Note dom0 output continues
	to be sent to the console along with Xen's output, no matter
	which way console input is currently set to go.

	In normal use the Xen console is not really of too much use
	(it's more for debugging the hypervisor itself), though it can
	be used to forcibly reboot the machine if the dom0 kernel is too
	locked up to do that itself, as well as to trigger NMIs.  The
	Xen console reacts to single key presses, with 'h' for help, and
	'R' to reboot.  Take care, this triggers an instant hard reboot
	of the machine.  Note if the dom0 kernel is running well enough
	to run xl(1) then "xl debug-keys keys" can also be used to send
	key-presses directly to Xen.

Note that "conswitch=ax" (i.e. adding a trailing 'x' to the Xen
command-line "conswitch=" option) can be used to prevent Xen from
switching console input to the dom0.

It is said in the Xen documentation that the conswitch character can be
modified at runtime, but I'm not quite sure yet how that is done.

--
					Greg A. Woods <gwoods%acm.org@localhost>

Kelowna, BC     +1 250 762-7675           RoboHack <woods%robohack.ca@localhost>
Planix, Inc. <woods%planix.com@localhost>     Avoncote Farms <woods%avoncote.ca@localhost>

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