[ 3.5.y.z extended stable ] Patch "doc, xen: Mention 'earlyprintk=xen' in the documentation." has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Mon Mar 4 20:49:12 UTC 2013

This is a note to let you know that I have just added a patch titled

    doc, xen: Mention 'earlyprintk=xen' in the documentation.

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see



>From d8c1ac937bb3a4add22604e180f958e41c687111 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Date: Mon, 25 Feb 2013 15:54:08 -0500
Subject: [PATCH] doc, xen: Mention 'earlyprintk=xen' in the documentation.

commit 2482a92e7d17187301d7313cfe5021b13393a0b4 upstream.

The earlyprintk for Xen PV guests utilizes a simple hypercall
(console_io) to provide output to Xen emergency console.

Note that the Xen hypervisor should be booted with 'loglevel=all'
to output said information.

Reported-by: H. Peter Anvin <hpa at zytor.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Link: http://lkml.kernel.org/r/1361825650-14031-2-git-send-email-konrad.wilk@oracle.com
Signed-off-by: H. Peter Anvin <hpa at linux.intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 Documentation/kernel-parameters.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a92c5eb..65f25d7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -760,6 +760,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.

 	earlyprintk=	[X86,SH,BLACKFIN]
+			earlyprintk=xen
@@ -777,6 +778,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			The VGA output is eventually overwritten by the real

+			The xen output can only be used by Xen PV guests.
 	ekgdboc=	[X86,KGDB] Allow early kernel console debugging


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