Re: Help adding trace events to xHCI

Sarah Sharp [off-list ref] writes:

My initial list of specific trace points was something like:

1. xHCI host initialization and shutdown

2. xHCI memory allocation (dynamic ring resizing, structure alloc, etc)

3. A few individual xHCI host controller command tracepoints:
   * status only for all completed commands
   * Address Device command status and output
   * Configure Endpoint and Evaluate Context output
   * individual trace points for other xHCI commands

4. Tracepoints for all USB transfer types:
   * Control TX output (only for non-successful transfers)
   * Bulk TX
   * Interrupt TX
   * Isoc TX

5. URB cancellation

And probably more.  Basically, I want to be able to control what gets
printed, based on where I think the xHCI bug might be.  Does that sound
reasonable?

Instead of individual trace points for command I would recommend to
consider just pushing the whole command buffer to the trace point and
parse the command in trace-cmd plugin in user space. Kernel code would
be simpler that way.

-- 
Kalle Valo