>Number:         30748
>Category:       port-hpcmips
>Synopsis:       Screen freezes after suspend/resume with ITE8181_LCD_CONTROL_ENABLE
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-hpcmips-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jul 14 16:54:00 +0000 2005
>Originator:     Svend Sorensen
>Release:        NetBSD 2.0.2
>Organization:
>Environment:
NetBSD ink.fakedomain.com 2.0.0_STABLE NetBSD 2.0.2_STABLE (IBMZ50) #0 Tue Jul5 16:27:47 PDT 2005 sorensen@sverige:/tmp/sorensen/src/sys/arch/hpcmips/compile/IBMz50 hpcmips
>Description:
With ITE8181_LCD_CONTROL_ENABLE option set, the screen on the IBM Z50 will blank when the system suspends.  The system normally resumes without any problems.  The power button initiates a suspend, and wakes the system up if it is suspended.

Occasionally, when resuming, the screen will display a set of vertical bars, and the system will be unresponsive.  The power button does not re-suspend the machine, and a hard reset (remove power cable, remove battery) is required.

The port-hpcmips mailing list has several posts regarding this issue.  Search the list for the string "vertical bars" (http://search.gmane.org/?query=vertical+bars&group=gmane.os.netbsd.ports.hpcmips).

I patched my kernel with the 'TLB out of universe' fix at http://www.city-net.com/~darkstar/netbsd/hpcmips.diff (see http://mail-index.netbsd.org/port-hpcmips/2004/12/30/0003.html).  I added the line:
options ITE8181_LCD_CONTROL_ENABLE
to the GENERIC kernel config and rebuilt it.
>How-To-Repeat:
Enable ITE8181_LCD_CONTROL_ENABLE (see http://netbsd.org/Ports/hpcmips/faq.html#z50-lcd).  Suspend the IBM Z50 by pressing the power button.  Resume the IBM Z50 by pressing the power button again.  Repeat until the screen displays vertical bars on resume.
>Fix:
Members of the port-hpcmips list suggested that running sync before suspending greatly reduced the probability of the issue arrising, but I did not find this to be the case.  When 'sync' did not work, I set up all partitions as read only, with mfs for /tmp and /var.  This eliminated any writes to the CF card, but the problem still arose.