[x200] Dock DisplayPort hotplug is broken

[ghost]

When docking an X200 with an external DisplayPort monitor, the latter isn't automatically attached. udevadm monitor doesn't show a single drm-related event.

Wten undocking an X200 with an external DisplayPort monitor, the latter isn't automatically detached either. udevadm monitor doesn't show a single drm-related event.

After (un)docking, one has to run xrandr to force detection of the DisplayPort output. Luckily, this can be bound to a hotkey as it works as a regular user.

However, with Wayland, xrandr no longer works at all..

I have found that running echo detect > /sys/class/drm/card0-HDMI-A-2/status as root forces re-detection of the DP link state, but this can't be run easily, and certainly not as a hotkey command.

Ideally, the (un)docking ACPI code should trigger drm udev events so the kernel automatically enables and disables DisplayPort output. This is much needed with Wayland at least.

[ghost]

Ugliest hack ever, but this seems to work with Wayland:

Add this to /etc/rc.local:

chmod 666 /sys/class/drm/card0-HDMI-A-2/status

Create /usr/local/bin/screen-hotplug:

#!/bin/sh

echo 'detect' > /sys/class/drm/card0-HDMI-A-2/status

Make it executable:

sudo chmod +x /usr/local/bin/screen-hotplug

Bind that script to a key, such as the blue ThinkVantage button. Press it every time you dock and every time you undock.

[swiftgeek]

Works for me with DP<>HDMI adapter, without any workarounds in X11 (enlightenment), wayland (weston) and even just plain VT HW: X200T