What is [ 0.4486641 ACPI PCC probe failed] starting version 219?

That message just stays there forever and I have to reload Ubuntu 15.04 all over again to continue using computer. I've loaded wine, PlayOnLinux, and a few games. Also loaded steam. All works well for awhile and then while booting up screen jams with the message:

[ 0.4486641 ACPI PCC probe failed] starting version 219

How can I fix the issue?

Solution 1:

If you are experiencing graphics issues it may be related to this bug https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-346-updates/+bug/1454817

However please read the following before you assume that issue

ACPI PPC Probe failed. Starting version 219

These are two separate messages

ACPI PPC Probe failed.

Starting version 219

The first is related to a new ACPI interface PCC (Platform Communication Channel) https://github.com/torvalds/linux/blob/master/drivers/mailbox/pcc.c

Which is defined by UEFI http://www.uefi.org/ACPIv5.1

The second is related to systemd the program start process manager for Ubuntu 15.04 and above the current version of systemd is 219 so the message Starting version 219 is just stating the boot process has begun. Noted here: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1432171

These messages are return prints of mutually exclusive events, they are not related to each other nor are they directly related to the Nvidia graphics issue.

You can see these messages without having any nvidia driver issues. Please do not assume you have a driver issue if you see these messages. Your PC may boot to the desktop after seeing one or both of them.

You may see this in your output of journalctl

sodu journalctl

Aug 16 23:10:55 x kernel: PCCT header not found.

Aug 16 23:10:55 x kernel: ACPI PCC probe failed.

These are the returns if the code does not find the ACPI interface which only some very new devices have or if it actually fails to read/write to the interface if it is present. The code was written for upstream releases. If you read the emails in the filed bugs below you will find information that supports my statements and you can read the return messages in the code itself in the github link above.

http://permalink.gmane.org/gmane.linux.power-management.general/56400 http://comments.gmane.org/gmane.linux.acpi.devel/73411

I hope this helps to clarify some things.