On 28 July 2015 at 15:45, Amit Pundir amit.pundir@linaro.org wrote:
Hi Tixy,
On 27 July 2015 at 23:34, Jon Medhurst (Tixy) tixy@linaro.org wrote:
Hi
With an ARM Landing Team branch based on LSK 3.18 Android I'm seeing a hang if I
echo 0 > /sys/devices/system/cpu/cpu1/online
After bisecting, I fixed this problem by reverting commit 553b785b5383 ("cpufreq: Iterate over all the possible cpus to create powerstats.")
So in this patch I believe instead of "for_each_possible_cpu" we should use "for_each_online_cpu". Can you please re-enable this patch and try this change?
Also if it doesn't work out, can you please tell more about this hang? Did the UI hang up on you? Did you see any panic or dmesg warnings/errors?
I did a quick test run of aosp/android-3.18 on qemu (with smp 2), but sadly my host machine couldn't keep up with multi-core qemu load and I didn't boot up all the way to UI. I booted up to shell prompt though and I did't see any unusual activity on shell prompt while I run following commands.
root@vexpress:/ # echo 0 > /sys/devices/system/cpu/cpu1/online [ 707.896250] CPU1: shutdown root@vexpress:/ # root@vexpress:/ # echo 1 > /sys/devices/system/cpu/cpu1/online [ 763.520081] CPU1: 2741 spurious wakeup calls [ 763.520164] CPU1: smp_ops.cpu_die() returned, trying to resuscitate [ 763.520344] CPU1: Booted secondary processor root@vexpress:/ # root@vexpress:/ # root@vexpress:/ # echo 0 > /sys/devices/system/cpu/cpu1/online [ 775.841608] CPU1: shutdown root@vexpress:/ # root@vexpress:/ # root@vexpress:/ # echo 1 > /sys/devices/system/cpu/cpu1/online [ 998.250284] CPU1: 23 spurious wakeup calls [ 998.250312] CPU1: smp_ops.cpu_die() returned, trying to resuscitate [ 998.250351] CPU1: Booted secondary processor
Next I'll give it an another shot on Juno. Can I boot Juno with non-LSK kernel i.e. only aosp/android-3.18 and ARM LT Juno platform patches? Or is there any dependency on LSK as well?
Regards, Amit Pundir
I was tempted to also revert the other scheduler and cpufreq mods from Google that are part of the same series, just as a precaution, because they don't fill me with confidence, but have left them in for now.
-- Tixy