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#[1]Index [2]Search [3]Interaction of Suspend code (S3) with the CPU
hotplug infrastructure [4]Runtime Power Management Framework for I/O
Devices
[5]The Linux Kernel
6.7.0
Quick search
____________________ Go
Contents
[X]
* [6]A guide to the Kernel Development Process
* [7]Submitting patches: the essential guide to getting your code
into the kernel
* [8]Code of conduct
* [9]Kernel Maintainer Handbook
* [10]All development-process docs
* [11]Core API Documentation
* [12]Driver implementer's API guide
* [13]Kernel subsystem documentation
+ [14]Core subsystems
o [15]Core API Documentation
o [16]Driver implementer's API guide
o [17]Memory Management Documentation
o [18]Power Management
o [19]Scheduler
o [20]Timers
o [21]Locking
+ [22]Human interfaces
+ [23]Networking interfaces
+ [24]Storage interfaces
* [25]Locking in the kernel
* [26]Linux kernel licensing rules
* [27]How to write kernel documentation
* [28]Development tools for the kernel
* [29]Kernel Testing Guide
* [30]Kernel Hacking Guides
* [31]Linux Tracing Technologies
* [32]fault-injection
* [33]Kernel Livepatching
* [34]Rust
* [35]The Linux kernel user's and administrator's guide
* [36]The kernel build system
* [37]Reporting issues
* [38]User-space tools
* [39]The Linux kernel user-space API guide
* [40]The Linux kernel firmware guide
* [41]Open Firmware and Devicetree
* [42]CPU Architectures
* [43]Unsorted Documentation
* [44]Translations
This Page
* [45]Show Source
How to get s2ram working[46]¶
2006 Linus Torvalds 2006 Pavel Machek
1. Check suspend.sf.net, program s2ram there has long whitelist of
"known ok" machines, along with tricks to use on each one.
2. If that does not help, try reading [47]swsusp/S3 tricks and
[48]Video issues with S3 resume. Perhaps problem is as simple as
broken module, and simple module unload can fix it.
3. You can use Linus' TRACE_RESUME infrastructure, described below.
Using TRACE_RESUME[49]¶
I've been working at making the machines I have able to STR, and almost
always it's a driver that is buggy. Thank God for the suspend/resume
debugging - the thing that Chuck tried to disable. That's often the
_only_ way to debug these things, and it's actually pretty powerful
(but time-consuming - having to insert TRACE_RESUME() markers into the
device driver that doesn't resume and recompile and reboot).
Anyway, the way to debug this for people who are interested (have a
machine that doesn't boot) is:
* enable PM_DEBUG, and PM_TRACE
* use a script like this:
#!/bin/sh
sync
echo 1 > /sys/power/pm_trace
echo mem > /sys/power/state
to suspend
* if it doesn't come back up (which is usually the problem), reboot
by holding the power button down, and look at the dmesg output for
things like:
Magic number: 4:156:725
hash matches drivers/base/power/resume.c:28
hash matches device 0000:01:00.0
which means that the last trace event was just before trying to
resume device 0000:01:00.0. Then figure out what driver is
controlling that device (lspci and /sys/devices/pci* is your
friend), and see if you can fix it, disable it, or trace into its
resume function.
If no device matches the hash (or any matches appear to be false
positives), the culprit may be a device from a loadable kernel
module that is not loaded until after the hash is checked. You can
check the hash against the current devices again after more modules
are loaded using sysfs:
cat /sys/power/pm_trace_dev_match
For example, the above happens to be the VGA device on my EVO, which I
used to run with "radeonfb" (it's an ATI Radeon mobility). It turns out
that "radeonfb" simply cannot resume that device - it tries to set the
PLL's, and it just _hangs_. Using the regular VGA console and letting X
resume it instead works fine.
NOTE[50]¶
pm_trace uses the system's Real Time Clock (RTC) to save the magic
number. Reason for this is that the RTC is the only reliably available
piece of hardware during resume operations where a value can be set
that will survive a reboot.
pm_trace is not compatible with asynchronous suspend, so it turns
asynchronous suspend off (which may work around timing or
ordering-sensitive bugs).
Consequence is that after a resume (even if it is successful) your
system clock will have a value corresponding to the magic number
instead of the correct date/time! It is therefore advisable to use a
program like ntp-date or rdate to reset the correct date/time from an
external time source when using this trace option.
As the clock keeps ticking it is also essential that the reboot is done
quickly after the resume failure. The trace option does not use the
seconds or the low order bits of the minutes of the RTC, but a too long
delay will corrupt the magic value.
©The kernel development community. | Powered by [51]Sphinx 5.0.1 &
[52]Alabaster 0.7.12 | [53]Page source
References
1. https://docs.kernel.org/genindex.html
2. https://docs.kernel.org/search.html
3. https://docs.kernel.org/power/suspend-and-cpuhotplug.html
4. https://docs.kernel.org/power/runtime_pm.html
5. https://docs.kernel.org/index.html
6. https://docs.kernel.org/process/development-process.html
7. https://docs.kernel.org/process/submitting-patches.html
8. https://docs.kernel.org/process/code-of-conduct.html
9. https://docs.kernel.org/maintainer/index.html
10. https://docs.kernel.org/process/index.html
11. https://docs.kernel.org/core-api/index.html
12. https://docs.kernel.org/driver-api/index.html
13. https://docs.kernel.org/subsystem-apis.html
14. https://docs.kernel.org/subsystem-apis.html#core-subsystems
15. https://docs.kernel.org/core-api/index.html
16. https://docs.kernel.org/driver-api/index.html
17. https://docs.kernel.org/mm/index.html
18. https://docs.kernel.org/power/index.html
19. https://docs.kernel.org/scheduler/index.html
20. https://docs.kernel.org/timers/index.html
21. https://docs.kernel.org/locking/index.html
22. https://docs.kernel.org/subsystem-apis.html#human-interfaces
23. https://docs.kernel.org/subsystem-apis.html#networking-interfaces
24. https://docs.kernel.org/subsystem-apis.html#storage-interfaces
25. https://docs.kernel.org/locking/index.html
26. https://docs.kernel.org/process/license-rules.html
27. https://docs.kernel.org/doc-guide/index.html
28. https://docs.kernel.org/dev-tools/index.html
29. https://docs.kernel.org/dev-tools/testing-overview.html
30. https://docs.kernel.org/kernel-hacking/index.html
31. https://docs.kernel.org/trace/index.html
32. https://docs.kernel.org/fault-injection/index.html
33. https://docs.kernel.org/livepatch/index.html
34. https://docs.kernel.org/rust/index.html
35. https://docs.kernel.org/admin-guide/index.html
36. https://docs.kernel.org/kbuild/index.html
37. https://docs.kernel.org/admin-guide/reporting-issues.html
38. https://docs.kernel.org/tools/index.html
39. https://docs.kernel.org/userspace-api/index.html
40. https://docs.kernel.org/firmware-guide/index.html
41. https://docs.kernel.org/devicetree/index.html
42. https://docs.kernel.org/arch/index.html
43. https://docs.kernel.org/staging/index.html
44. https://docs.kernel.org/translations/index.html
45. https://docs.kernel.org/_sources/power/s2ram.rst.txt
46. https://docs.kernel.org/power/s2ram.html#how-to-get-s2ram-working
47. https://docs.kernel.org/power/tricks.html
48. https://docs.kernel.org/power/video.html
49. https://docs.kernel.org/power/s2ram.html#using-trace-resume
50. https://docs.kernel.org/power/s2ram.html#note
51. http://sphinx-doc.org/
52. https://github.com/bitprophet/alabaster
53. https://docs.kernel.org/_sources/power/s2ram.rst.txt
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