Re: [PATCH v4 13/14] cxl: Add a dev_dbg() when a decoder was added to a port

[Dan Williams]

Robert Richter wrote:
> Improve debugging by adding and unifying messages whenever a decoder
> was added to a port. It is especially useful to get the decoder
> mapping of the involved CXL host bridge or PCI device. This avoids a
> complex lookup of the decoder/port/device mappings in sysfs.

I am not opposed to this debug statement, but I hope that most use cases
for associating objects are handled by tooling and we don't need to keep
extending kernel debug statements for these queries.

E.g.: show all the decoders and targets of port1

# cxl list -PT -p 1 -Di
[
  {
    "port":"port1",
    "host":"pci0000:34",
    "depth":1,
    "decoders_committed":0,
    "nr_dports":1,
    "dports":[
      {
        "dport":"0000:34:00.0",
        "id":0
      }
    ],
    "decoders:port1":[
      {
        "decoder":"decoder2.0",
        "interleave_ways":1,
        "state":"disabled"
      },
      {
        "decoder":"decoder2.1",
        "interleave_ways":1,
        "state":"disabled"
      },
      {
        "decoder":"decoder2.2",
        "interleave_ways":1,
        "state":"disabled"
      },
      {
        "decoder":"decoder2.3",
        "interleave_ways":1,
        "state":"disabled"
      },
      {
        "decoder":"decoder1.0",
        "interleave_ways":1,
        "state":"disabled",
        "nr_targets":1,
        "targets":[
          {
            "target":"0000:34:00.0",
            "position":0,
            "id":0
          }
        ]
      }
    ]
  }
]