I had already found the reason for this behavior! The only change in the "drivers/base/power/" Subdirectory is inside main.c line 192.
There is a "while loop" that loops over a list (dpm_list). The (principal) task of this loop is to call "device_prepare" on every list-element. Every element that is processed (without error) is then removed from the list and placed into a "prepared" list (I leave out the special case of EAGAIN here, because its not necessary to understood the bug). In the prev. version this loop is terminated when the list is empty OR when there is an error. In the newer revision the second condition was removed. Removing the second condition will result in an endless loop whenever an error occurs! Right now I am not sure what will be the correct way to handle an error (on device_prepare)... I guess that the correct way should be to "skip/mark" this element, continue to process the rest of the elements and do special handling later on the marked elements. But, because the prev. revision simply ignores the failed element AND all remaining (I believe that the second part is definitely wrong) , this should work here too. I am currently trying to generate a kernel with this line reverted to prev. version and check if this works.. I will report (again) if my checks are done -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-signed-hwe-5.13 in Ubuntu. https://bugs.launchpad.net/bugs/1966125 Title: Suspend (to ram) fails after upgrade from 5.13.0-35-generic to 5.13.0-37-generic Status in linux-signed-hwe-5.13 package in Ubuntu: Confirmed Bug description: As stated in the summary, my PC can't suspend anymore after kernel upgrade. When I click suspend from desktop: - The screen gets blank - (sometimes) Screen then shows up for a short time, then gets blank again - Now PC ist "dead", no reaction an keyboard, mouse and so on. - Even a CTR-ALT-DEL didn't show any reaction. - There is still some activity (HD-Led flashing) - The PC is "reachable" via network, but trying to ssh into it will not work (no response after entering password) - I have to reboot, either by power the PC off by pressing the power button longer or by using "Magic SysRq" keyboard sequence When I rollback (I use systemback) to Kernel 5.13.0-35-generic suspend works! ################################################################# Information needed as directed by https://wiki.ubuntu.com/DebuggingKernelSuspend) ################################################################# ============================= $cat /proc/acpi/wakeup Device S-state Status Sysfs node GPP0 S4 *enabled pci:0000:00:01.1 GP12 S4 *enabled pci:0000:00:07.1 GP13 S4 *enabled pci:0000:00:08.1 XHC0 S4 *enabled pci:0000:0e:00.3 GP30 S4 *disabled GP31 S4 *disabled PS2K S3 *disabled GPP2 S4 *disabled GPP3 S4 *disabled GPP8 S4 *enabled pci:0000:00:03.1 SWUS S4 *enabled pci:0000:0a:00.0 SWDS S4 *enabled pci:0000:0b:00.0 GPP1 S4 *enabled pci:0000:00:01.2 ============================= sudo sh -c "sync && echo 1 > /sys/power/pm_trace && pm-suspend" ... after power up again ... dmesg | grep -e "Magic number" -e "hash matches" [ 3.141067] PM: Magic number: 0:247:389 [ 3.145394] PM: hash matches drivers/base/power/main.c:982 [ 3.149741] thermal cooling_device4: hash matches ============================= sudo su echo freezer > /sys/power/pm_test exit sudo sh -c "sync && echo 1 > /sys/power/pm_trace && pm-suspend" ... promt is back after a few seconds again ... dmesg | grep -e "Magic number" -e "hash matches" [ 3.142991] PM: Magic number: 14:995:344 [ 3.147383] tty tty61: hash matches [ 3.151721] acpi ACPI0007:06: hash matches ============================= sudo su echo devices > /sys/power/pm_test exit sudo sh -c "sync && echo 1 > /sys/power/pm_trace && pm-suspend" ... after power up again ... dmesg | grep -e "Magic number" -e "hash matches" [ 3.141229] PM: Magic number: 0:247:394 [ 3.145558] PM: hash matches drivers/base/power/main.c:982 [ 3.149905] thermal cooling_device9: hash matches ============================= sudo su echo platform > /sys/power/pm_test exit sudo sh -c "sync && echo 1 > /sys/power/pm_trace && pm-suspend" ... after power up again ... dmesg | grep -e "Magic number" -e "hash matches" [ 3.142816] PM: Magic number: 0:247:394 [ 3.147180] PM: hash matches drivers/base/power/main.c:982 [ 3.151573] thermal cooling_device9: hash matches ============================= sudo su echo processors > /sys/power/pm_test exit sudo sh -c "sync && echo 1 > /sys/power/pm_trace && pm-suspend" ... after power up again ... dmesg | grep -e "Magic number" -e "hash matches" [ 3.141830] PM: Magic number: 0:247:394 [ 3.146148] PM: hash matches drivers/base/power/main.c:982 [ 3.150488] thermal cooling_device9: hash matches ============================= sudo su echo core > /sys/power/pm_test exit sudo sh -c "sync && echo 1 > /sys/power/pm_trace && pm-suspend" ... after power up again ... dmesg | grep -e "Magic number" -e "hash matches" [ 3.140971] PM: Magic number: 0:247:394 [ 3.145294] PM: hash matches drivers/base/power/main.c:982 [ 3.149639] thermal cooling_device9: hash matches ============================= sudo su echo none > /sys/power/pm_test exit sudo sh -c "sync && echo 1 > /sys/power/pm_trace && pm-suspend" ... after power up again ... dmesg | grep -e "Magic number" -e "hash matches" [ 3.143489] PM: Magic number: 0:247:394 [ 3.147856] PM: hash matches drivers/base/power/main.c:982 [ 3.152244] thermal cooling_device9: hash matches ============================= $ sudo cat /sys/kernel/debug/suspend_stats success: 0 fail: 0 failed_freeze: 0 failed_prepare: 0 failed_suspend: 0 failed_suspend_late: 0 failed_suspend_noirq: 0 failed_resume: 0 failed_resume_early: 0 failed_resume_noirq: 0 failures: last_failed_dev: last_failed_errno: 0 0 last_failed_step: ============================= ################################################################# System information: ################################################################# ============================= lsb_release -rd Description: Ubuntu 20.04.4 LTS Release: 20.04 ============================= ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.13.0-37-generic 5.13.0-37.42~20.04.1 ProcVersionSignature: Ubuntu 5.13.0-37.42~20.04.1-generic 5.13.19 Uname: Linux 5.13.0-37-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.21 Architecture: amd64 CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Wed Mar 23 21:15:22 2022 InstallationDate: Installed on 2020-12-30 (448 days ago) InstallationMedia: SourcePackage: linux-signed-hwe-5.13 UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-5.13/+bug/1966125/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
