Kernel Patches Test Suspend States at Runtime
Two patches by Rafael J. Wysocki give users the ability to test suspend and hibernation modes at runtime to detect errors.
The first patch gives users the ability to test the suspend code (suspend to disk) without actually switching to suspend mode. This is a useful approach to discovering driver issues says the developer. The second patch modifies the current hibernation function (Suspend to RAM) source code to achieve the same objective. According to Wysocki, this works better than the current test modes as his code can also test globabl ACPI methods.
The test options add a new "/sys/power/pm_test_level" attribute which accepts numbers between 1 and 5. Each of these values simulates a different suspend or hibernation code level. Wysocki explains the individual values as follows. 5 test the freezing of individual processes. 4 additionally tests suspending of devices. Besides suspending processes and devices, 3 additionally tests platform global methods. 2 adds disabling of nonboot CPUs, and 1 simulates full system suspend.
The developer adds: "if a suspend is started by normal means, the suspend core will perform its normal operations up to the point indicated by the test level. Next, it will wait for 5 seconds and carry out the resume operations needed to transition the system back to the fully functional state". To avoid using the text system, you can set "pm_test_level" to 0. Wysocki’s third patch adds information on his test systems to the documentation.
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
New Steam Client Ups the Ante for Linux
The latest release from Steam has some pretty cool tricks up its sleeve.
-
Gnome OS Transitioning Toward a General-Purpose Distro
If you're looking for the perfectly vanilla take on the Gnome desktop, Gnome OS might be for you.
-
Fedora 41 Released with New Features
If you're a Fedora fan or just looking for a Linux distribution to help you migrate from Windows, Fedora 41 might be just the ticket.
-
AlmaLinux OS Kitten 10 Gives Power Users a Sneak Preview
If you're looking to kick the tires of AlmaLinux's upstream version, the developers have a purrfect solution.
-
Gnome 47.1 Released with a Few Fixes
The latest release of the Gnome desktop is all about fixing a few nagging issues and not about bringing new features into the mix.
-
System76 Unveils an Ampere-Powered Thelio Desktop
If you're looking for a new desktop system for developing autonomous driving and software-defined vehicle solutions. System76 has you covered.
-
VirtualBox 7.1.4 Includes Initial Support for Linux kernel 6.12
The latest version of VirtualBox has arrived and it not only adds initial support for kernel 6.12 but another feature that will make using the virtual machine tool much easier.
-
New Slimbook EVO with Raw AMD Ryzen Power
If you're looking for serious power in a 14" ultrabook that is powered by Linux, Slimbook has just the thing for you.
-
The Gnome Foundation Struggling to Stay Afloat
The foundation behind the Gnome desktop environment is having to go through some serious belt-tightening due to continued financial problems.
-
Thousands of Linux Servers Infected with Stealth Malware Since 2021
Perfctl is capable of remaining undetected, which makes it dangerous and hard to mitigate.