Comment 18 for bug 1488426

The above working patch has been merged in linux-4.1.y branch of linux-stable repository as can been seen here: https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?qt=grep&q=mmc%3A+core%3A+Enable+runtime+PM+management+of+host+devices&h=linux-4.1.y

Since Ubuntu 15.10 comes with Kernel version 4.2, I guess using Ubuntu 15.10 would fix the issue. I would wait for 14.04.4 to come out in Feb 2016 with updated kernel as depicted here: https://wiki.ubuntu.com/Kernel/LTSEnablementStack#Kernel.2BAC8-Support.A14.04.x_Ubuntu_Kernel_Support

And then upgrade to Ubuntu 16.04 LTS.