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Diffstat (limited to 'Documentation/power/basic-pm-debugging.txt')
| -rw-r--r-- | Documentation/power/basic-pm-debugging.txt | 41 |
1 files changed, 32 insertions, 9 deletions
diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt index 1555001bc73..edeecd447d2 100644 --- a/Documentation/power/basic-pm-debugging.txt +++ b/Documentation/power/basic-pm-debugging.txt @@ -15,7 +15,7 @@ test at least a couple of times in a row for confidence. [This is necessary, because some problems only show up on a second attempt at suspending and resuming the system.] Moreover, hibernating in the "reboot" and "shutdown" modes causes the PM core to skip some platform-related callbacks which on ACPI -systems might be necessary to make hibernation work. Thus, if you machine fails +systems might be necessary to make hibernation work. Thus, if your machine fails to hibernate or resume in the "reboot" mode, you should try the "platform" mode: # echo platform > /sys/power/disk @@ -172,15 +172,14 @@ you can boot the kernel with the 'no_console_suspend' parameter and try to log kernel messages using the serial console. This may provide you with some information about the reasons of the suspend (resume) failure. Alternatively, it may be possible to use a FireWire port for debugging with firescope -(ftp://ftp.firstfloor.org/pub/ak/firescope/). On x86 it is also possible to -use the PM_TRACE mechanism documented in Documentation/s2ram.txt . +(http://v3.sk/~lkundrak/firescope/). On x86 it is also possible to +use the PM_TRACE mechanism documented in Documentation/power/s2ram.txt . 2. Testing suspend to RAM (STR) To verify that the STR works, it is generally more convenient to use the s2ram tool available from http://suspend.sf.net and documented at -http://en.opensuse.org/s2ram . However, before doing that it is recommended to -carry out STR testing using the facility described in section 1. +http://en.opensuse.org/SDB:Suspend_to_RAM (S2RAM_LINK). Namely, after writing "freezer", "devices", "platform", "processors", or "core" into /sys/power/pm_test (available if the kernel is compiled with @@ -195,10 +194,34 @@ Among other things, the testing with the help of /sys/power/pm_test may allow you to identify drivers that fail to suspend or resume their devices. They should be unloaded every time before an STR transition. -Next, you can follow the instructions at http://en.opensuse.org/s2ram to test -the system, but if it does not work "out of the box", you may need to boot it -with "init=/bin/bash" and test s2ram in the minimal configuration. In that -case, you may be able to search for failing drivers by following the procedure +Next, you can follow the instructions at S2RAM_LINK to test the system, but if +it does not work "out of the box", you may need to boot it with +"init=/bin/bash" and test s2ram in the minimal configuration. In that case, +you may be able to search for failing drivers by following the procedure analogous to the one described in section 1. If you find some failing drivers, you will have to unload them every time before an STR transition (ie. before you run s2ram), and please report the problems with them. + +There is a debugfs entry which shows the suspend to RAM statistics. Here is an +example of its output. + # mount -t debugfs none /sys/kernel/debug + # cat /sys/kernel/debug/suspend_stats + success: 20 + fail: 5 + failed_freeze: 0 + failed_prepare: 0 + failed_suspend: 5 + failed_suspend_noirq: 0 + failed_resume: 0 + failed_resume_noirq: 0 + failures: + last_failed_dev: alarm + adc + last_failed_errno: -16 + -16 + last_failed_step: suspend + suspend +Field success means the success number of suspend to RAM, and field fail means +the failure number. Others are the failure number of different steps of suspend +to RAM. suspend_stats just lists the last 2 failed devices, error number and +failed step of suspend. |