** Changed in: linaro-ubuntu
Status: Fix Committed => Fix Released
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https://bugs.launchpad.net/bugs/971091
Title:
Pandaboard ES freezes with the default CPU scaling governor ondemand
Status in Linaro Texas Instruments Landing Team:
Fix Released
Status in Linaro Ubuntu Engineering Builds:
Fix Released
Status in “linux-ti-omap4” package in Ubuntu:
Fix Released
Bug description:
Pandaboard ES freezes sporadically with the CPU scaling governor default
setting, which is "ondemand".
It is a complete freeze, no syslog entry, no serial access, no network, no
keyboard/mouse anymore. When pressing the reset button, it will not even
reboot. The SD card interface seems to be hanging. Pulling and re-inserting the
SD card before pressing the reset button, or a global power-cycle will re-boot
the board properly.
The error occurs during normal operation on desktop, but can also be procuded
in an unattended way:
1. Create a RAM disk by adding this to fstab
none /tmp tmpfs defaults,noatime,mode=1777,size=600M 0 0
2. Mount it and create a big file on the RAM disk:
dd bs=1M count=210 if=/dev/urandom of=/tmp/a
3. Change to /tmp and start an endless loop:
while true; do cp a b; date; sleep 3; done
Note that the "sleep" is important to cause the governor to switch CPU
speed up and down. Wait for 1 to 8 hrs and find the Pandaboard ES in
frozen state. You can do the same with a bigger file and /tmp on the
SD card. This will often produce the error faster (possibly due to CPU
idling at flash write delays) but will stress your flash card.
Setting the CPU scaling governor to "performance" completely solves the
problem. I guess there might be a HW issue on the Pandaboard ES that kicks in
with frequent CPU speed changes.
Solution proposal: set the CPU scaling governor to "performance" as default
until the issue is further analysed.
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-1411-omap4 3.2.0-1411.14
ProcVersionSignature: Ubuntu 3.2.0-1411.14-omap4 3.2.9
Uname: Linux 3.2.0-1411-omap4 armv7l
ApportVersion: 1.95-0ubuntu1
Architecture: armhf
Date: Sun Apr 1 23:01:52 2012
ProcEnviron:
TERM=xterm
LANG=de_DE.UTF-8
SHELL=/bin/bash
SourcePackage: linux-ti-omap4
UpgradeStatus: No upgrade log present (probably fresh install)
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