summary refs log tree commit diff
path: root/Documentation
diff options
context:
space:
mode:
authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-02-25 15:54:08 -0500
committerH. Peter Anvin <hpa@linux.intel.com>2013-02-25 13:41:18 -0800
commit2482a92e7d17187301d7313cfe5021b13393a0b4 (patch)
treeff6af9e9cb48da1e898e0916c9ebf5f74b57bdcb /Documentation
parent565d956a7e191e95d81f515196951715f2616e6b (diff)
downloadlinux-2482a92e7d17187301d7313cfe5021b13393a0b4.tar.gz
doc, xen: Mention 'earlyprintk=xen' in the documentation.
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@zytor.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/1361825650-14031-2-git-send-email-konrad.wilk@oracle.com
Cc: <stable@vger.kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6c723811c0a0..c4cc199e32cb 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -754,6 +754,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
 	earlyprintk=	[X86,SH,BLACKFIN]
 			earlyprintk=vga
+			earlyprintk=xen
 			earlyprintk=serial[,ttySn[,baudrate]]
 			earlyprintk=ttySn[,baudrate]
 			earlyprintk=dbgp[debugController#]
@@ -771,6 +772,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			The VGA output is eventually overwritten by the real
 			console.
 
+			The xen output can only be used by Xen PV guests.
+
 	ekgdboc=	[X86,KGDB] Allow early kernel console debugging
 			ekgdboc=kbd