Ubuntu 14.04 issue of SDIO kernel support (sdhci-acpi)

check reference links below.

http://serverphorums2.rssing.com/browser.php?indx=20361555&item=4129

http://ubuntuhandbook.org/index.php/2014/08/install-upgrade-linux-kernel-3-16/

Simply, update your kernel up to 3.16

2. For 64-bit system:

cd /tmp/

wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.16-utopic/linux-headers-3.16.0-031600-generic_3.16.0-031600.201408031935_amd64.deb

wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.16-utopic/linux-headers-3.16.0-031600_3.16.0-031600.201408031935_all.deb

wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.16-utopic/linux-image-3.16.0-031600-generic_3.16.0-031600.201408031935_amd64.deb

sudo dpkg -i linux-headers-3.16.0-*.deb linux-image-3.16.0-*.deb

Reboot and done.

If for some reason this kernel release doesn’t work properly for you, reboot into previous kernel (Grub -> Advanced -> select previous kernel) and run this command to remove Linux Kernel 3.16:

sudo apt-get remove linux-headers-3.16.0-* linux-image-3.16.0-*

Finally update grub menu:

sudo update-grub

*********** might be useful for realtek rtl8723bs module ************

http://ubuntuforums.org/showthread.php?t=2249936