I have the same problem on Lenovo S435 and ubuntu-mate 15.10 on 4.2.0-30-generic x86_64 dual boot with Windows 8.1.
But this problem started only after bios update from BBCN16WW(V1.03) to BBCN16WW(V1.07). With the previous bios V1.03 this never happened, even with the same kernel.
I have the same problem on Lenovo S435 and ubuntu-mate 15.10 on 4.2.0-30-generic x86_64 dual boot with Windows 8.1.
But this problem started only after bios update from BBCN16WW(V1.03) to BBCN16WW(V1.07). With the previous bios V1.03 this never happened, even with the same kernel.