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x86/doc: mini-howto for using earlyprintk=dbgp

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From: Linux Kernel Mailing List
Subject: x86/doc: mini-howto for using earlyprintk=dbgp
Date: Monday, March 30, 2009 - 12:37 pm

Gitweb:     http://git.kernel.org/linus/a1aade478862fca8710904532cbc6efed97fd05a
Commit:     a1aade478862fca8710904532cbc6efed97fd05a
Parent:     e56d0cfe7790fd3218ae4f6aae1335547fea8763
Author:     Yinghai Lu <yinghai@kernel.org>
AuthorDate: Wed Mar 4 16:11:35 2009 -0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu Mar 5 10:57:52 2009 +0100

    x86/doc: mini-howto for using earlyprintk=dbgp
    
    [ mingo: small edits and extensions. ]
    
    Signed-off-by: Yinghai Lu <yinghai@kernel.org>
    Cc: "Eric W. Biederman" <ebiederm@xmission.com>
    Cc: Greg KH <gregkh@suse.de>
    Cc: Randy Dunlap <randy.dunlap@oracle.com>
    Cc: Alan Stern <stern@rowland.harvard.edu>
    Cc: Sarah Sharp <sarah.a.sharp@intel.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    LKML-Reference: <49AF18B7.4050305@kernel.org>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 Documentation/x86/earlyprintk.txt |  101 +++++++++++++++++++++++++++++++++++++
 1 files changed, 101 insertions(+), 0 deletions(-)

diff --git a/Documentation/x86/earlyprintk.txt b/Documentation/x86/earlyprintk.txt
new file mode 100644
index 0000000..607b1a0
--- /dev/null
+++ b/Documentation/x86/earlyprintk.txt
@@ -0,0 +1,101 @@
+
+Mini-HOWTO for using the earlyprintk=dbgp boot option with a
+USB2 Debug port key and a debug cable, on x86 systems.
+
+You need two computers, the 'USB debug key' special gadget and
+and two USB cables, connected like this:
+
+  [host/target] <-------> [USB debug key] <-------> [client/console]
+
+1. There are three specific hardware requirements:
+
+ a.) Host/target system needs to have USB debug port capability.
+
+ You can check this capability by looking at a 'Debug port' bit in
+ the lspci -vvv output:
+
+ # lspci -vvv
+ ...
+ 00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03) (prog-if 20 [EHCI])
+         Subsystem: Lenovo ThinkPad T61
+         Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ...
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Previous thread: x86: pre-initialize boot_cpu_data.x86_phys_bits to avoid system_state tests by Linux Kernel Mailing List on Monday, March 30, 2009 - 12:37 pm. (1 message)

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