Bug 156705

Summary: Serial console corrupt on boot
Product: Red Hat Enterprise Linux 4 Reporter: David Woodhouse <dwmw2>
Component: kernelAssignee: Jason Baron <jbaron>
Status: CLOSED ERRATA QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.0CC: kjetilho, knoel, tao, t.h.amundsen
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Whiteboard:
Fixed In Version: RHSA-2005-514 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2005-10-05 13:04:45 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 156322    
Attachments:
Description Flags
patch to recalculate divisor as appropriate.
none
Updated patch none

Description David Woodhouse 2005-05-03 15:04:31 UTC 
When booting with serial console on a machine with a National Semiconductor
SuperIO chip where the BIOS enables its high speed mode, the initialisation of
the serial driver switches it into high-speed mode without fixing up the baud rate. 

The result is that the port suddenly ends up running four times faster than it
should, and the last non-garbage thing we see on the serial console is the
serial driver's initialisation message.

The fix is to adjust the baud rate divisor at the same time as we adjust the
master clock...
Comment 1 David Woodhouse 2005-05-03 15:04:31 UTC 
Created attachment 113967 [details]
patch to recalculate divisor as appropriate.
Comment 2 David Woodhouse 2005-05-06 10:06:05 UTC 
Created attachment 114075 [details]
Updated patch

This is the form in which the patch was sent upstream. With the original
problem fixed, the 'ifndef ppc' hack isn't required either.
Comment 3 David Woodhouse 2005-05-24 10:46:01 UTC 
*** Bug 158107 has been marked as a duplicate of this bug. ***
Comment 4 Kjetil T. Homme 2005-06-15 22:42:51 UTC 
we added this to /etc/rc.sysinit as a workaround:

/bin/setserial /dev/ttyS0 spd_normal
/bin/stty 9600 < /dev/ttyS0

quite early, just after ". /etc/init.d/functions" worked for us.  we don't get
all the boot messages, but it's workable.
Comment 9 Red Hat Bugzilla 2005-10-05 13:04:45 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2005-514.html
Comment 10 David Woodhouse 2005-10-11 14:08:47 UTC 
*** Bug 167117 has been marked as a duplicate of this bug. ***