[SRU][BIONIC] after enabling cppc dmesg fills with "ACPI CPPC: PCC check channel failed. Status=0"
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| linux (Ubuntu) |
Incomplete
|
High
|
Manoj Iyer | ||
Bug Description
[Impact]
On ARM64 systems enabling cppccontrol=1 in firmware, the dmesg fills with messages like:
[ 4083.960332] ACPI CPPC: PCC check channel failed. Status=0
[ 4085.546975] ACPI CPPC: PCC check channel failed. Status=0
[ 4113.939921] ACPI CPPC: PCC check channel failed. Status=0
[ 4115.531777] ACPI CPPC: PCC check channel failed. Status=0
We lose any useful data in dmesg and on the console.
[Fix]
upstream commit fixes this issue:
commit 3d41386d556db9f
Author: George Cherian <email address hidden>
Date: Fri Mar 23 03:30:31 2018 -0700
cpufreq: CPPC: Use transition_delay_us depending transition_latency
[Testing]
-- before kernel patch --
Both console output and dmesg are filled with the message
ACPI CPPC: PCC check channel failed. Status=0
[ 85.969952] ACPI CPPC: PCC check channel failed. Status=0
[ 81.888445] cloud-init[4810]: Cloud-init v. 18.2 running 'modules:final' at Fri, 13 Apr 2018 19:11:57 +0000. Up 80.71 seconds.
[ 81.888625] cloud-init[4810]: Cloud-init v. 18.2 finished at Fri, 13 Apr 2018 19:11:58 +0000. Datasource DataSourceMAAS [http://
[ OK ] Started Execute cloud user/final scripts.
[ OK ] Reached target Cloud-init target.
[ 86.230432] ACPI CPPC: PCC check channel failed. Status=0
[ 86.701943] ACPI CPPC: PCC check channel failed. Status=0
[ 86.773668] ACPI CPPC: PCC check channel failed. Status=0
[ 87.369958] ACPI CPPC: PCC check channel failed. Status=0
[ 87.733361] ACPI CPPC: PCC check channel failed. Status=0
[ 88.207372] ACPI CPPC: PCC check channel failed. Status=0
ubuntu@starbuck:~$ uname -a
Linux starbuck 4.15.0-13-generic #14-Ubuntu SMP Sat Mar 17 13:44:36 UTC 2018 aarch64 aarch64 aarch64 GNU/Linux
-- after kernel patch --
OK ] Started Apply the settings specified in cloud-config.
Starting Execute cloud user/final scripts...
[ 67.178425] cloud-init[3688]: Cloud-init v. 18.2 running 'modules:final' at Fri, 13 Apr 2018 20:41:15 +0000. Up 65.98 seconds.
[ 67.200190] cloud-init[3688]: Cloud-init v. 18.2 finished at Fri, 13 Apr 2018 20:41:15 +0000. Datasource DataSourceMAAS [http://
[ OK ] Started Execute cloud user/final scripts.
[ OK ] Reached target Cloud-init target.
Ubuntu Bionic Beaver (development branch) starbuck ttyAMA0
starbuck login:
ubuntu@starbuck:~$ uname -a
Linux starbuck 4.15.0-15-generic #16~lp1763817+
[Regression Potential]
None.
| Changed in linux (Ubuntu): | |
| assignee: | nobody → Canonical Kernel Team (canonical-kernel-team) |
| description: | updated |
| description: | updated |
| Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote Missing required logs. | #1 |
| Changed in linux (Ubuntu): | |
| status: | New → Incomplete |
| tags: | added: bionic |
| description: | updated |
| Changed in linux (Ubuntu): | |
| assignee: | Canonical Kernel Team (canonical-kernel-team) → Manoj Iyer (manjo) |
| Matt Dirba (5qxm) wrote | #2 |
| Matt Dirba (5qxm) wrote | #3 |
| tags: | added: cscc |
This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1763817
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.