I tried various kernels, also 4.4.19-040419, which previously solved the problem for me, but doesn't do so now. I will try 4.8.0-997 again to see if it solves the issue. I'm on a Thinkpad X1 Carbon (first generation) with an Intel HD 5550 using a Broadwell CPU, so this bug is not limited to Skylake CPUs it seems.
I tried various kernels, also 4.4.19-040419, which previously solved the problem for me, but doesn't do so now. I will try 4.8.0-997 again to see if it solves the issue. I'm on a Thinkpad X1 Carbon (first generation) with an Intel HD 5550 using a Broadwell CPU, so this bug is not limited to Skylake CPUs it seems.