in hyperv ubuntu 14.04 not getting full screen

i tried sudo vi /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT
sudo apt-get install linux-image-3.11.0-15-generic linux-headers-3.11.0-15-generic

GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash video=hyperv_fb:1680×1050″ in /etc/default/grub.

but i’m not getting fullscreen. it is a microsoft surface please help me on this