On 10/25/2012 05:07:01 PM, Srivatsan Canchivaram wrote:
Hi,
I have a modem with a Freescale MPC8313E processor. I am trying to
enable
power savings in the processor by placing it in Standby mode and
resume
normal operation with a Wake-On-LAN magic packet.
Following the directions in the Freescale Power Management app note, I
enabled Power Management Support in the Linux kernel and device tree
configurations.
I ran the following command on the board:
echo standby > /sys/power/state
This caused the console to hang and there was no further response to
keyboard inputs. I enabled ‘no_console_suspend’ in the kernel and
when I
loaded the new build and enabled standby mode, I observed an Oops
trace:
RASCOM_QCU.7.0.0013 $ echo standby > /sys/power/state
<6>PM: Syncing fFreezing user space processes ... ilesystems ...
<7>PM:
Entering standby sleep
Unable to handle kernel paging request for instruction fetch
Faulting instruction address: 0x616d6570
Oops: Kernel access of bad area, sig: 11 [#1]
MPC831x RDB
Modules linked in: dsp rcspi modem i2c_mpc thermal_sys lm92 hwmon
[last
unloaded: modem]
NIP: 616d6570 LR: c0165224 CTR: 616d6573
REGS: cd087d30 TRAP: 0400 Not tainted (2.6.27)
MSR: 20001032 <ME,IR,DR> CR: 28002024 XER: 20000000
TASK = cc312400[1196] 'echo' THREAD: cd086000
GPR00: 00000002 cd087de0 cc312400 cf821800 cd087de8 00000002 c06e0000
c06da4a0
GPR08: c06da948 616d6573 00003fff c06c6308 28002022 10091248 0fffc000
100050b8
GPR16: 1008a270 10068810 100687c8 10068814 00000000 1008c284 1008c294
c0246180
GPR24: c02ab9e4 c02ab9dc c06cc4f4 00000006 cd087e08 00000002 c06c595c
cf821808
NIP [616d6570] 0x616d6570
LR [c0165224] platform_pm_suspend_noirq+0x84/0x88
What kernel are you using? platform_pm_suspend_noirq was removed by
this commit:
commit 9b39e73d0c2b265a7f8748b0e9a9f09be84079a8
Author: Rafael J. Wysocki <r...@sisk.pl>
Date: Sun Dec 18 00:34:24 2011 +0100
PM / Sleep: Remove forward-only callbacks from platform bus type
The forward-only PM callbacks provided by the platform bus type are
not necessary any more, because the PM core executes driver
callbacks
when the corresponding subsystem callbacks are not present, so drop
them.
Signed-off-by: Rafael J. Wysocki <r...@sisk.pl>
It seems that a driver's pm ops are getting corrupted -- maybe used
after freeing? Have you tried enabling slab/slub debug?
Can you instrument the code to see if there are any fields in the
device struct that aren't corrupt, that could point out which device
this is?
I found another thread that dealt with Power Management issues on the
Freescale MPC8313 processor:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-January/095240.html
The resolution of this issue seems to be related to the JTAG TRST pin
being
disabled. This is not relevant in my case as the TRST on my board is
already inactive.
If you were seeing that, you'd see a hang rather than an oops.
-Scott
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