I am trying to diagnose a problem where I get video output on Thunderbolt on one DisplayPort, but no output on the second DisplayPort. I would love to turn on all the (kernel-level) logging output that there is, but do not know how to do that. Basically, on a Dell Inspiron 16 Plus (7610) laptop with Thunderbolt 4, I am running Fedora Linux 36 with kernel 5.17+. Connecting that laptop to a Thunderbolt docking station (Intel Thunderbolt 3 chip inside), with two screens attached via DisplayPort, I get only one screen up and running. I'd like to discover more about this apparent error mode, because attaching a different TB3 setup works fine. I am looking for some means to enable logging or to get debugging insight. Generally speaking, I suspect that this specific Dell laptop (configuration) has some challenges in the BIOS, and with Thunderbolt in general, but am totally blind to what is going on. This system offers potential for fun, this being a hybrid PRIME configuration, with an Intel iGPU passing through to an Nvidia dGPU which seems to be the only wired-up way to get DisplayPort output.
