I have an Inspiron 11 3000 Series. Just ran Windows Update today and there was an optional update for "Intel Corporation - Other Hardware - Intel(R) Serial IO I2C ES Controller" Published 05/13/2015. After I install this through Windows Update the Dell touchpad stops working properly. Touchpad becomes sluggish and unresponsive and you can't access the Synaptics settings anymore. Also when looking in Device Manager it is not there anymore and Serial IO I2C appears with a yellow exclamation mark.
Had to go to Device Manager and rollback the driver for Intel Serial IO I2C ES Controller (it went back to 2013 driver version instead of 2015) but now there are no more issues in device manager and the touchpad works fine after reboot.
What is "Intel Serial IO I2C ES Controller" and whats up with the latest update for it that Microsoft is trying to push through Windows Update?