Re: System will not suspend with highest numbered CPU offline [REGRESSION][BISECTED]

[Viresh Kumar <viresh.kumar@linaro.org>]

On 04-09-15, 16:59, Rafael J. Wysocki wrote:
> On Thursday, September 03, 2015 02:40:43 PM Doug Smythies wrote:
> > As of, or about, Kernel 4.2RC1 if I take my highest numbered
> > CPU offline (7 in my case), the system will not suspend.
> 
> Does "will not suspend" mean that the suspend will fail with an error
> or will it crash or hang or something else?
> 
> > The issue persists through Kernel 4.2.
> > This is on my test computer with an i7-2600K.
> > I do not normally use suspend on this computer,
> > but was doing so while working on a bug report.
> > 
> > The kernel was bisected, and the result was:
> > 
> > $ git bisect bad
> > 87549141d516aee71d511138e27117c41e8aef68 is the first bad commit
> > commit 87549141d516aee71d511138e27117c41e8aef68
> > Author: Viresh Kumar <viresh.kumar@linaro.org>
> > Date:   Wed Jun 10 02:13:21 2015 +0200
> > 
> > cpufreq: Stop migrating sysfs files on hotplug
> > 
> > See also several e-mails with the above subject line
> > between June 8th and 10th.
> > 
> > With any other combination of taking CPUs offline,
> > not including CPU 7, suspend seems to work properly.
> 
> Well, we'll need to debug it some.
> 
> Can you please check what's in the
> 
> /sys/devices/system/cpu/cpuX/cpufreq/related_cpus
> 
> files for all CPUs on your system?

I wanted to give him some patch to debug it a bit more, but couldn't
do that whole day.

@Doug: Can you please enable DEBUG for cpufreq with this:

diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 9fde14544ead..c09945aa7f17 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -1,3 +1,4 @@
+subdir-ccflags-y  := -DDEBUG
 # CPUfreq core
 obj-$(CONFIG_CPU_FREQ)                 += cpufreq.o freq_table.o


And give us the outputs of both successful and unsuccessful logs?

+ the values of both affected_cpus and related_cpus fields for all
CPUs.

-- 
viresh