Check _PLD isn't align ACPI spec 6.5

[More Shih]

ACPI spec. doesn't prohibit the use of _UPC only, and it doesn't prohibit the use of _UPC & _PLD to declare a hidden/invisible lane.

[Ivan Hu (ivan.hu)]

Right, ACPI spec. doesn't prohibit the use of _UPC, _PLD, but it is not define the _PLD hidden/invisible lane as well. firmware implemented with all unused USB _PLD set to 0, it does cause kernel Warnings and have been discussed with Linux kernel upstream maintainer.
you can check with the bug and patch for the details,
https://bugs.launchpad.net/fwts/+bug/2055855
https://lists.ubuntu.com/archives/fwts-devel/2024-March/013842.html

[More Shih (mshihubuntu)]

The Linux is fixed the issue that description as below

Recent FWTS change was made to prevent Linux PM warning messages, which made all legacy and ongoing programs got bug reported with this tool. Mathias confirmed respective Linux patch for that particular warning message is available in Linux kernel version 6.8+. With that said, Linux kernel change is right way to do instead of changing tool or BIOS.

Patches -
https://<email address hidden>/
https://<email address hidden>

[Ivan Hu (ivan.hu)]

@More,

Right, the linux kernel fix the warnings, but we still believe this should be some potential issue for Bios implementation. It is not make sense that _UPC claimed not connectable , but still get _PLD method with invalid value. Is there any particular reason for this?
Although it doesn't have any actual impact on functionality, and FWTS does not rank it as a critical or high failure, it is worth keeping the test to find and warn about potential BIOS implementation issues.

[More Shih (mshihubuntu)]

1st the change didn't align the ACPI Spec description. Please let me know what the potential issue cause by aligns with ACPI spec.
2nd the original change made all legacy and ongoing programs got bug reported with this tool. It caused related tester to confuse report the problem due to the tool report it failed. The test result show as below. The either way is made a new change to "Warn", not a failure case.
Other failures: NONE

Test |Pass |Fail |Abort|Warn |Skip |Info |
---------------+-----+-----+-----+-----+-----+-----+

acpi_time | 3| | | | 18| |
acpi_wpc | | | | | 14| |
acpiinfo | | | | | | 3|
acpipld | | 1| | | | |

[Ivan Hu (ivan.hu)]

@More,

Thanks for your information, we've downgraded the failure to a warning and the patch have been pushed.
https://lists.ubuntu.com/archives/fwts-devel/2024-August/013872.html