Error parsing PCC subspaces from PCCT
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Low
|
Unassigned | ||
Bionic |
Fix Released
|
Undecided
|
dann frazier |
Bug Description
[Impact]
A scary-looking message appears in dmesg in several places during boot:
"Error parsing PCC subspaces from PCCT"
This could cause users to believe they have buggy firmware, in cases where it's actually fine.
[Test Case]
dmesg | grep "Error parsing PCC subspaces"
[Fix]
Resolved in upstream commit that cleanly cherry-picks back to bionic:
8f8027c5f935 mailbox: PCC: erroneous error message when parsing ACPI PCCT
[Regression Risk]
PCC is a generic ACPI-defined mechanism for the OS and firmware to communicate. Since the fix does change how the tables are parsed, regression scenarios could include breakages in PCC clients (things that use this layer to communicate to firmware). The only Kconfig option I see in bionic's source that depends on CONFIG_PCC is the CPPC library, which provides ACPI CPU performance management used by the cppc-cpufreq driver and is used by the scaling driver/governor for Sandy bridge processors.
Tested on an Nvidia DGX system. This is an upstream fix, so any regressions will have upstream support.
description: | updated |
Changed in linux (Ubuntu): | |
importance: | Undecided → High |
Changed in linux (Ubuntu): | |
status: | Expired → Confirmed |
description: | updated |
Changed in linux (Ubuntu Bionic): | |
status: | New → Confirmed |
assignee: | nobody → dann frazier (dannf) |
description: | updated |
Changed in linux (Ubuntu Bionic): | |
status: | Confirmed → Fix Committed |
Changed in linux (Ubuntu): | |
status: | Confirmed → Fix Committed |
tags: |
added: verification-done-bionic removed: verification-needed-bionic |
tags: | added: cscc |
This change was made by a bot.