Linux – Debugging a suspend to ram issue with PM_TRACE

debuggingkernel-moduleslinux-kernelsuspend

So I've been debugging a hairy suspend-to-ram issue, where I get

Oct 12 15:41:23 arjundesktop dbus[2863]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'
Oct 12 15:41:23 arjundesktop systemd[1]: Reached target Sleep.
Oct 12 15:41:23 arjundesktop systemd[1]: Starting Suspend...
Oct 12 15:41:23 arjundesktop systemd[1]: Starting Network Manager Script Dispatcher Service...
Oct 12 15:41:23 arjundesktop systemd-sleep[17199]: Suspending system...
�������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������May 21 16:33:31 arjundesktop rsyslogd: [origin software="rsyslogd" swVersion="8.4.2" x-pid="2929" x-info="http://www.rsyslog.com"] start

When this happens, I can no longer wakeup my system. I've run this on debian and ubuntu, with kernels ranging from 3.16 – 4.7. My current kernel is

Linux arjundesktop 4.7.6 #1 SMP Sat Oct 8 13:00:22 MDT 2016 x86_64 GNU/Linux

I've been following this basic guide to suspend debugging. My dmesg log shows

May 21 16:33:31 arjundesktop kernel: [    1.225463] initcall deferred_probe_initcall+0x0/0x70 returned 0 after 87 usecs
May 21 16:33:31 arjundesktop kernel: [    1.225863] calling  late_resume_init+0x0/0x1a0 @ 1
May 21 16:33:31 arjundesktop kernel: [    1.226255]   Magic number: 14:34:278
May 21 16:33:31 arjundesktop kernel: [    1.226655] tty tty15: hash matches
May 21 16:33:31 arjundesktop kernel: [    1.227075] initcall late_resume_init+0x0/0x1a0 returned 0 after 799 usecs
May 21 16:33:31 arjundesktop kernel: [    1.227466] calling  rtc_hctosys+0x0/0x101 @ 1
May 21 16:33:31 arjundesktop kernel: [    1.227889] rtc_cmos 00:02: setting system clock to 2014-01-01 12:16:03 UTC (1388578563)
May 21 16:33:31 arjundesktop kernel: [    1.228291] initcall rtc_hctosys+0x0/0x101 returned 0 after 423 usecs

What does this magic number mean? Why is saying the crash happened from my tty? When I run

cat /sys/power/pm_trace_dev_match

I get

usb
tty

What does this mean? How would I proceed? Output of lsusb

Bus 004 Device 002: ID 8087:8001 Intel Corp. 
Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 002: ID 8087:8009 Intel Corp. 
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 062a:4101 Creative Labs 
Bus 001 Device 002: ID 045e:00db Microsoft Corp. Natural Ergonomic Keyboard 4000 V1.0
Bus 001 Device 005: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Best Answer

I have no real answers, but I changed my graphics card from an AMD 7950 to a AMD Vega 64. Now suspend to ram works fine on the amdgpu driver, so I suspect it was a graphics driver issue.

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