Re: [PATCH 7/8] cpufreq: Preserve policy structure across suspend/resume

From: Srivatsa S. Bhat
Date: Mon Jul 15 2013 - 07:56:35 EST


On 07/15/2013 03:51 PM, Viresh Kumar wrote:
> On 15 July 2013 15:35, Srivatsa S. Bhat
> <srivatsa.bhat@xxxxxxxxxxxxxxxxxx> wrote:
>> Actually even I was wondering about this while writing the patch and
>> I even tested shutdown after multiple suspend/resume cycles, to verify that
>> the refcount is messed up. But surprisingly, things worked just fine.
>
> What kind of system have you tested it on?
>

The system has 2 sockets with 8 cores each, and has Intel Sandybridge
CPUs. I had used a local patch to simulate CPU hotplug in the suspend-to-ram
path using the freeze state of pm_test (because I had other problems in
using the 'processors' state of pm_test). The patch is shown below:


diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index ece0422..fe07b77 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -342,8 +342,13 @@ static int enter_state(suspend_state_t state)
if (error)
goto Unlock;

- if (suspend_test(TEST_FREEZER))
+ if (suspend_test(TEST_FREEZER)) {
+ pr_debug("Disabling nonboot CPUs\n");
+ disable_nonboot_cpus();
+ pr_debug("Enabling nonboot CPUs\n");
+ enable_nonboot_cpus();
goto Finish;
+ }

pr_debug("PM: Entering %s sleep\n", pm_states[state]);
pm_restrict_gfp_mask();



Regards,
Srivatsa S. Bhat

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