Improved USB4 Debugging Support With Linux 6.13

Along with the staging changes, Greg Kroah-Hartman this morning also sent out the USB/Thunderbolt changes for the nearly-over Linux 6.13 merge window.

There isn't any shiny new hardware support or next-gen USB capabilities for Linux 6.13 but the most exciting aspect is improved debugging of problematic USB4/Thunderbolt hardware. Greg KH explained in the USB pull request:

"Overall, a pretty slow development cycle, the majority of the work going into the debugfs interface for the thunderbolt (i.e. USB4) code, to help with debugging the myrad ways that hardware vendors get their interfaces messed up."

Via DebugFS is now much more information being readily exposed to user-space for helping developers understand USB4/Thunderbolt issues. Among the newly-exposed USB4 information via DebugFS in Linux 6.13 are exposing USB4 Gen 4 margining capabilities, asymetic lane margining, and other bits. The patch series behind the USB4 v2 Gen 4 lane margining bits explains that this code is useful on the manufacturing floor of devices to check the stability of the electrical signaling.

More details on all of the USB changes to find with the Linux 6.13 feature code via this pull request.