GP107GLM [Quadro P1000 Mobile]: frequent failure to initialize displays on Thunderbolt dock

Submitted by Markus Wanner

Assigned to Nouveau Project

Link to original bug (#110993)

Description

When connecting to the Thunderbolt 3 Dock, the monitors attached to it more often remain black rather than showing a proper image. Sometimes the Laptop freezes entirely, other times just one of the two comes up, most of the time, they remain black and eventually enter standby.

I'm using a Lenovo P1 featuring a Quadro P1000 Mobile GPU. An integrated GPU is wired to the internal display as eDP-1. The Nvidia card exposes an HDMI port on the laptop. Plugging a monitor there directly usually works. Vie the docking station, I get another 3 ports controlled by the Nvidia GPU. These are either HDMI or DisplayPort. I have two monitors for experimentation, a Dell one and a Lenovo one.

I'm running a Linux 5.2-rc5 kernel and the nouveau driver compiled from a current checkout of the git repo of Ben Skeggs (https://github.com/skeggsb/nouveau/tree/f91e915b6a12c281aed4401a869881f293b72d4e). Most of the time, I'm running with the runpm_fixes of Karol Herbst (that is the last five revisions from https://github.com/karolherbst/nouveau/tree/runpm_fixes).

The output of grep . /sys/class/drm/card*-*/status after a start w/o the dock or any display attached is:

/sys/class/drm/card0-eDP-1/status:connected
/sys/class/drm/card1-DP-1/status:disconnected
/sys/class/drm/card1-DP-2/status:disconnected
/sys/class/drm/card1-HDMI-A-1/status:connected
/sys/class/drm/card1-eDP-2/status:disconnected

I'll provide further details of what I did together with the corresponding kernel logs with tracing enabled in follow-up comments and attachments.