Bug 45161

Summary:	Suspend/resume fails with pm_test=processors on Sony VAIO VPCSB2C5E
Product:	ACPI	Reporter:	Alessandro Pignotti (alexpigna.dev)
Component:	Power-Sleep-Wake	Assignee:	Aaron Lu (aaron.lu)
Status:	CLOSED INSUFFICIENT_DATA
Severity:	normal	CC:	aaron.lu, chihchun
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	3.2.0	Subsystem:
Regression:	No	Bisected commit-id:

Description Alessandro Pignotti 2012-07-26 16:45:07 UTC

Machine: Sony VAIO VPCSB2C5E
Processor: Intel(R) Core(TM) i5-2520M CPU

using pm-suspend with /sys/power/pm_test set to freezer,devices and platform succeed even when repeating the test several times.

When set to "processors" the machine hangs, although I'm not sure if it hangs during suspend or resume. Sysrqs keys does not work either after the hang.

After disabling all processors but cpu0 suspend worked reliably.

I'm available to do deeper debugging, if needed. Currently I don't know where to start.

Comment 1 Alessandro Pignotti 2012-07-26 17:06:31 UTC

Probably related, I did this after a fresh boot:

sudo bash -c "echo 0 > /sys/devices/system/cpu/cpu1/online"
sudo bash -c "echo 1 > /sys/devices/system/cpu/cpu1/online"
sudo bash -c "echo 0 > /sys/devices/system/cpu/cpu1/online"

The last command hangs, the system is responsive but it never returns. Any idea about how to debug this?

Comment 2 Alessandro Pignotti 2012-07-27 16:12:36 UTC

I've spent some time debugging the issue. Using printks I have been able to find out that the hang happens in the method called

cpu_stop_cpu_callback

And exactly in the case CPU_POST_DEAD inside the switch. The call to kthread_stop never returns.

At this point I don't think that ACPI is the proper component to report the bug in. Any suggestion about a more proper place? Also any hint on how to move forward in the investigation is very welcome.

Comment 3 Rex Tsai 2012-11-09 07:54:12 UTC

Please find the proposed fix here - http://permalink.gmane.org/gmane.linux.kernel/1038828

Comment 4 Aaron Lu 2013-02-21 06:58:02 UTC

Hi Alessandro,

Can you please report if the fix mentioned by Rex can solve your problem? Thanks.

Comment 5 Aaron Lu 2013-04-17 08:02:59 UTC

ping