[Bug 2054391] Re: Fix CPU thermal sensors enumeration

[Christian Ehrhardt ]

Local test build has been happy as well.

You test description is not wrong, but a bit too incomplete for what an SRU should have.
"Check the output of thermald" could use some "how exactly" and good/bad case examples.

I got a system in testflinger with a modern CPU hoping it would expose
this issue to test and try to improve that to be more acceptable.

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https://bugs.launchpad.net/bugs/2054391

Title:
  Fix  CPU thermal sensors enumeration

Status in HWE Next:
  New
Status in thermald package in Ubuntu:
  Fix Released
Status in thermald source package in Jammy:
  Confirmed

Bug description:
  [Impact]
  Some CPU sensors are not enumerated, this can make thermald deviates from the correct behavior of the CPU TDP.

  [Fix]
  Traverse all sensors under hwmon sysfs directory to make sure everything is enumerated.

  [Test]
  Check the output of thermald. Once the fix is in place, thermal zones that are previously omitted now shows up:
  [INFO]Zone 1: AMBF, Active:1 Bind:1 Sensor_cnt:1
  To do so
  0. get a large machine which will have more thermal zones
  1. stop the potentially auto-running service
     $ systemctl stop thermald
  2. run the daemon in foreground with loglevel to see what is going on.
     On many modern systemd (=the large ones) it might not know the CPUid,
     to bypass that for the test you can ask it to ignore the check
     $ sudo thermald --no-daemon --loglevel=info --ignore-cpuid-check
  3. check the output
     On init the system will be probed and that will show something like:

  ...
   ZONE DUMP BEGIN
  [1718954645][INFO]Zone 2: cpu, Active:1 Bind:0 Sensor_cnt:1
  ...
  [1718954645][INFO]Zone 3: cpu, Active:1 Bind:0 Sensor_cnt:1
  ...
   ZONE DUMP END

  In here, on systems with many thermal zones one would before the fix
  only see a few, and with the fix more zones.


  [Where problems could occur]
  Since the new logic traverse the whole hwmon sysfs, the startup time can take slightly longer.

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