As asked in comment #36, I've installed the package xserver-xorg-video-intel_2.19.0-0ubuntu1~xup1_i386.deb and did *not* solve this issue: got a black screen lock still with working mouse after 4 lid close/open.
However, the error message in X log disappeared.
As asked in comment #36, I've installed the package xserver- xorg-video- intel_2. 19.0-0ubuntu1~ xup1_i386. deb and did *not* solve this issue: got a black screen lock still with working mouse after 4 lid close/open.
However, the error message in X log disappeared.