path: root/Documentation/power/basic-pm-debugging.txt
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authorTakashi Iwai <tiwai@suse.de>2016-08-25 17:56:09 +0200
committerTakashi Iwai <tiwai@suse.de>2016-08-25 17:56:09 +0200
commita820cd3d25c2891028b5f296a8a871ce6dd92c0d (patch)
tree3e86aeb1b898e9ca0dd6754dc7e6ff68865ee175 /Documentation/power/basic-pm-debugging.txt
parentabaa2274811d607679e8687b4118c4922a3517ac (diff)
parentcfb89f2e7505c6823020a18bbdc5410284305234 (diff)
Merge tag 'asoc-fix-v4.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Fixes for v4.8 A clutch of fixes for v4.8. These are mainly driver specific, the most notable ones being those for OMAP which fix a series of issues that broke boot on some platforms there when deferred probe kicked in. There's also one core fix for an issue when unbinding a card which for some reason had managed to not manifest until recently.
Diffstat (limited to 'Documentation/power/basic-pm-debugging.txt')
1 files changed, 26 insertions, 1 deletions
diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt
index b96098ccfe69..708f87f78a75 100644
--- a/Documentation/power/basic-pm-debugging.txt
+++ b/Documentation/power/basic-pm-debugging.txt
@@ -164,7 +164,32 @@ load n/2 modules more and try again.
Again, if you find the offending module(s), it(they) must be unloaded every time
before hibernation, and please report the problem with it(them).
-c) Advanced debugging
+c) Using the "test_resume" hibernation option
+/sys/power/disk generally tells the kernel what to do after creating a
+hibernation image. One of the available options is "test_resume" which
+causes the just created image to be used for immediate restoration. Namely,
+after doing:
+# echo test_resume > /sys/power/disk
+# echo disk > /sys/power/state
+a hibernation image will be created and a resume from it will be triggered
+immediately without involving the platform firmware in any way.
+That test can be used to check if failures to resume from hibernation are
+related to bad interactions with the platform firmware. That is, if the above
+works every time, but resume from actual hibernation does not work or is
+unreliable, the platform firmware may be responsible for the failures.
+On architectures and platforms that support using different kernels to restore
+hibernation images (that is, the kernel used to read the image from storage and
+load it into memory is different from the one included in the image) or support
+kernel address space randomization, it also can be used to check if failures
+to resume may be related to the differences between the restore and image
+d) Advanced debugging
In case that hibernation does not work on your system even in the minimal
configuration and compiling more drivers as modules is not practical or some