xref: /freebsd/tools/cam/README (revision 240c614d48cb0484bfe7876decdf6bbdcc99ba73)
1This directory has snippets of what will eventually become camio. This program
2can take an expression for the types of things to trace, and then custom write a
3dtrace script to do that.
4
5camio is a d-traced tcpdump-like program for examining CAM traffic (and
6therefore I/O and other traffic to storage media) that written during covid, but
7with fbp providers that recent clang optimizations make unuseable, hence the
8shift to the cam provider, but retooling them and finishing the grammar will
9take some time (but these scripts are useful today).
10
11mpr.d and mps.d give insight into the completion path for the mpr and mps SIMs.
12You really have to read through the driver to understand, but it's the central
13point of the driver and most of the I/O already had the proper CAM status code,
14but the reset does not. These scripts use the generic completion hook to show
15the exceptional cases (many of which have printfs that can be enabled, but often
16aren't). The completion hook should give one enough tools to puzzle out what's
17going on for weird, but repeatable problems.
18