tree 8564ccf99de56e11e7b1f6f5396bb710633536e6
parent aca86d059b92947cd5e430a5d4d1f1fee2ff5b89
author Brandon Wyman <bjwyman@gmail.com> 1657658823 +0000
committer Brandon Wyman <bjwyman@gmail.com> 1657816831 +0000

psu-ng: Fix false brownout fault logging

The hasVINUVCount only matters if a power supply is present. Issues
noticed on an internal system test on Rainier 1S4U, during the
replacement of a power supply with a fan fault, a 110000AC PEL
(brownout) was logged.

If we have two power supplies total, then have a fault on one of them,
in the act of replacing it, we will remove input voltage, and then
remove the power supply. If the power supply is missing, and it
previously had an input under-voltage fault, it does not really count
against a brownout anymore, other than now being missing. We already
account for present power supplies, the issue appears to be with
counting VIN_UV faults against missing power supplies. Only count a
power supply as VIN_UV faulted if it is present.

Tested:
    Simulated Rainier 2S2U
      1. Fake fan fault psu0.
      2. Fake VIN_UV fault psu0 (remove power).
      3. Remove psu0
      4. Install psu0, apply power (clear all faults).
      5. Verify no brownout fault logged.
      6. Repeat for psu1
    Simulated Rainier 2S2U
      Re-run brownout fault script.
      Verify brownout fault logged.
    Real Rainier 1S4U
      1. Remove psu2.
      2. Insert obstruction to block fan.
      3. Install psu2.
      4. Wait for PSU fan fault to be logged.
      5. Remove psu2.
      6. Remove fan obstruction from PSU.
      7. Install psu2.
      8. Verify no brownout fault logged.
      9. Repeat for psu3.

Change-Id: I809112ca0afc0b8294b62a62cdcc147b51ccc6e6
Signed-off-by: Brandon Wyman <bjwyman@gmail.com>