Hello Scott, I am using 2.6.27 - I am trying to add Power Management support to an older product.
Thanks, Srivatsan On Fri, Oct 26, 2012 at 8:27 PM, Scott Wood <scottw...@freescale.com> wrote: > 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 9b39e73d0c2b265a7f8748b0e9a9f0**9be84079a8 > 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<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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