Comment 100 for bug 1275794

I tried today vanilla 3.13 on my T440s. Still the same issue. I then inserted the udelay (at the same position stated in the patch) as well as uncommented locks in ironlake_panel_vdd_work (I had boot hangs with the full patch of Georg Pichler applied).

I only have a HDMI device, which is connected to the dock. I booted undocked and docked then. At first, several messages (including the mode information) appeared, however I had no freeze. Then, when I enable the output (using xrandr --output DP2 --auto), the system freezes for several minutes but after a while, I have output on HDMI! My log (dmesg_3.13_docking_hdmi_with_udelay) looks a bit different then others do, especially this every reoccurring intel_dp_set_signal_levels.