problem seems to be in package ubuntu-drivers-common...
upgrading it from v0.2.91.5 to v0.2.91.6 from trusty-proposed repo on Jun 27th caused the same problem as upgrading it from v0.2.91.5 to v0.2.91.7 from trusty-updates this time
I was only able to downgrade it to v0.2.91.4 using synaptics. However, problem is gone... Everythig works fine now...
problem seems to be in package ubuntu- drivers- common. ..
upgrading it from v0.2.91.5 to v0.2.91.6 from trusty-proposed repo on Jun 27th caused the same problem as upgrading it from v0.2.91.5 to v0.2.91.7 from trusty-updates this time
I was only able to downgrade it to v0.2.91.4 using synaptics. However, problem is gone... Everythig works fine now...