Saturday, 29 August 2015

Identifying Suspend/Resume delays

The Intel SuspendResume project aims to help identify delays in suspend and resume.  After seeing it demonstrated by Len Brown (Intel) at this years Linux Plumbers conference I gave it a quick spin and was delighted to see how easy it is to use.

The project has some excellent "getting started" documentation describing how to configure a system and run the suspend resume analysis script which should be read before diving in too deep.

For the impatient, one can do try it out using the following:

git clone
cd suspendresume
sudo ./

..and manually resume once after the machine has completed a successful suspend.

This will create a directory containing dumps of the kernel log and ftrace output as well as an html web page that one can read into your favourite web browser to view the results.  One can zoom in/out of the web page to drill down and see where the delays are occurring, an example from the SuspendResume project page is shown below:

example webpage (from

It is a useful project, kudos to Intel for producing it.  I thoroughly recommend using it to identify the delays in suspend/resume.

Friday, 7 August 2015

More ACPI table tests in fwts 15.08.00

The Canonical Hardware Enablement Team and myself are continuing the work to add more ACPI table tests to the Firmware Test Suite (fwts).  The latest 15.08.00 release added sanity checks for the following tables:
The release also added a test for the ACPI _CPC revision 2 control method and we updated the ACPICA core to version 20150717.

Our aim is to continue to add support for existing and new ACPI tables to make fwts a comprehensive firmware test tool.  For more information about fwts, please refer to the fwts jump start wiki page.