Patch-ID# 104108-01
Keywords: Cray Virtual Console cvc cvcredir boot panic CS6400 cray4d
Synopsis: SunOS 5.4 CS6400: cvc panic during boot
Date: Nov/19/96

Solaris Release: 2.4_CS6400

SunOS release: 5.4_CS6400

Unbundled Product:

Unbundled Release:

Topic: SunOS 5.4 CS6400: cvc panic during boot
NOTE: 
   NOTE 1:	This patch replaces the Cray patch C641019-02.  You do
		not need to install this patch if you have already
		installed C641019-02.

   NOTE 2:	BugID's with six digits or less are related to Cray SPR's.

BugId's fixed with this patch: 86421 88162
 
Changes incorporated in this version:

Relevant Architectures: sparc

Patches accumulated and obsoleted by this patch: 641019-02

Patches which conflict with this patch:

Patches required with this patch:

Obsoleted by:

Files included with this patch:

/kernel/drv/cvc
/kernel/drv/cvcredir

Problem Description:

(from C641019-02)

88162: CVC PANIC ON BOOTUP FOLLOWING MESSAGE "WARNING: CVC_REDIR: CVCINPUT_Q NULL!"

System can panic during startup flow under certain timing conditions.
The specific cause is the cvcd daemon opens its CVC devices
_before_ the kernel has set up its console descriptor.  This is not a bug
in itself, but it causes the panic in the cvc driver because the driver
doesn't properly handle this scenario.

(from C641019-01)

86421: CVC PANICS ON HIGH OUTPUT BOOT SEQUENCE

When booting with alot of console output, the kernel may panic in cvc driver
(cvc_wput).  A race condition can occur between the time the cvcoutput_q 
is initialized and the streams queue is actually enabled.  This fix 
combines the two operation to guarantee nobody attempts to use cvcoutput_q
before it is completely ready.  We recreated the problem by booting with 
debug versions of the "ip" and "arp" drivers and setting moddebug to 
0x80000000 (booted w/kadb).

Patch Installation Instructions:
--------------------------------
Refer to the Install.info file within the patch for instructions on
using the generic 'installpatch' and 'backoutpatch' scripts provided
with each patch. Any other special or non-generic installation
instructions should be described below.

Special Install Instructions:
-----------------------------

none
