FYI, we noticed the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply.git fixes commit 5bc28b93a36e3cb3acc2870fb75cb6ffb182fece ("power_supply: power_supply_read_temp only if use_cnt > 0") on test machine: vm-kbuild-yocto-ia32: 1 threads qemu-system-x86_64 -enable-kvm -cpu Westmere with 320M memory caused below changes: [ 5.180382] __power_supply_register: Expected proper parent device for 'test_ac' [ 5.181219] __power_supply_register: Expected proper parent device for 'test_battery' [ 5.182252] thermal thermal_zone0: failed to read out thermal zone (-19) [ 5.182916] __power_supply_register: Expected proper parent device for 'test_usb' FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -cpu Westmere -kernel /pkg/linux/x86_64-randconfig-s3-06222353/gcc-6/5bc28b93a36e3cb3acc2870fb75cb6ffb182fece/vmlinuz-4.7.0-rc1-00001-g5bc28b9 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-kbuild-yocto-ia32-2/bisect_boot-1-yocto-minimal-i386.cgz-x86_64-randconfig-s3-06222353-5bc28b93a36e3cb3acc2870fb75cb6ffb182fece-20160623-81162-1kedsbh-1.yaml ARCH=x86_64 kconfig=x86_64-randconfig-s3-06222353 branch=linux-devel/devel-spot-201606222332 commit=5bc28b93a36e3cb3acc2870fb75cb6ffb182fece BOOT_IMAGE=/pkg/linux/x86_64-randconfig-s3-06222353/gcc-6/5bc28b93a36e3cb3acc2870fb75cb6ffb182fece/vmlinuz-4.7.0-rc1-00001-g5bc28b9 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-kbuild-yocto-ia32/yocto-minimal-i386.cgz/x86_64-randconfig-s3-06222353/gcc-6/5bc28b93a36e3cb3acc2870fb75cb6ffb182fece/0 LKP_SERVER=inn earlyprintk=ttyS0,115200 systemd.log_level=err debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal rw ip=::::vm-kbuild-yocto-ia32-2::dhcp drbd.minor_count=8' -initrd /fs/sda1/initrd-vm-kbuild-yocto-ia32-2 -m 320 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sda1/disk0-vm-kbuild-yocto-ia32-2,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-kbuild-yocto-ia32-2 -serial file:/dev/shm/kboot/serial-vm-kbuild-yocto-ia32-2 -daemonize -display none -monitor null Thanks, Xiaolong