vim /etc/default/grub
Change one of the line to the following:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
update-grub
#To fix problems with corners after waking up PC
dconf write /org/pantheon/desktop/gala/mask-corners false
vim /etc/default/grub
Change one of the line to the following:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
update-grub
#To fix problems with corners after waking up PC
dconf write /org/pantheon/desktop/gala/mask-corners false