As mentioned in bug #1318038, booting the upstream kernel http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.15-rc5-utopic/linux-image-3.15.0-031500rc5-generic_3.15.0-031500rc5.201405091635_amd64.deb did not make any difference.
As mentioned in bug #1318038, booting the upstream kernel http:// kernel. ubuntu. com/~kernel- ppa/mainline/ v3.15-rc5- utopic/ linux-image- 3.15.0- 031500rc5- generic_ 3.15.0- 031500rc5. 201405091635_ amd64.deb did not make any difference.