Hey there,

My name's Peter and I'm working with the linux-omap-pm kernel on the
Gumstix Overo board for an academic project.

Back when the linux-omap-pm branch was still on 2.6.33-rc8, I could
compile and run the kernel on the Overo without any problems. Suspend to
memory (via mem > /sys/power/state) worked just fine. Unfortunately,
ever since 2.6.34-rcX releases started coming out, I have been running
into problems:

First of all, I was under the impression that omap3_pm_defconfig was
supposed to more-or-less work "out of the box". This has not been the
case, as when I try to compile:

make ARCH=arm omap3_pm_defconfig
make ARCH=arm -j4 uImage
CROSS_COMPILE=/opt/arm-2009q3/bin/arm-none-linux-gnueabi-

I get these error messages back.

arch/arm/mach-omap2/omap44xx-smc.S: Assembler messages:
arch/arm/mach-omap2/omap44xx-smc.S:30: Error: missing expression -- `smc'
make[1]: *** [arch/arm/mach-omap2/omap44xx-smc.o] Error 1
make: *** [arch/arm/mach-omap2] Error 2

Fortunately, this is solved by using menuconfig and un-checking the
OMAP4 in System Type (this shouldn't affect anything, as the Overo is
using the OMAP3...)

Unfortunately, after building that, when I try to boot the Overo, this
is as far as it gets:

## Booting kernel from Legacy Image at 82000000 ...
   Image Name:   Linux-2.6.34-rc3-09551-gb301cc7
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    1994520 Bytes =  1.9 MB
   Load Address: 80008000
   Entry Point:  80008000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK
OK

Starting kernel ...

Uncompressing Linux... done, booting the kernel.

I have no idea if it simply hangs here, or it is working and simply not
printing anything to the serial console. (If it helps at all, the
processor *seems* warm, but I cannot be sure of this).

To see if the problem can be solved by going back to 2.6.33, I do a git
checkout of the corresponding branch:

git checkout -b stable v2.6.33

I compile with the attached .config file, and the overo boots up just
fine (though at some point in the process modprobe complains to me about
omaplfb not found...)

However, now when I try to suspend, I get this:

root@overo:~# echo mem > /sys/power/state
PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.01 seconds) done.
Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done.
Suspending console(s) (use no_console_suspend to debug)
PM: suspend of devices complete after 109.004 msecs
PM: late suspend of devices complete after 0.274 msecs
Class driver suspend failed for cpu0
PM: early resume of devices complete after 0.030 msecs
PM: resume of devices complete after 343.597 msecs
Restarting tasks ... done.

The "Class driver suspend failed for cpu0" is what concerns me, and I've
tried a lot of stuff and have remained unable to get suspend working again.

To summarize, my questions are:

1. Why do the 2.6.34-rcX kernels stop at "Uncompressing Linux... done,
booting the kernel."?
2. Why does the 2.6.33 kernel fail to suspend with "Class driver suspend
failed for cpu0"? Did I incorrectly perform the git checkout, or did I
misconfigure something?
3. And finally, for my future work, since I am interested in power
management, is there a possible solution to suspending to disk? (Perhaps
termed "hibernate")

I would greatly appreciate any pointers in the right direction so I can
get this working again. Thanks a lot for your time and attention.

Peter Tseng