diff options
| author | Rafael J. Wysocki <rjw@sisk.pl> | 2012-02-13 16:29:47 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rjw@sisk.pl> | 2012-02-17 23:36:30 +0100 |
| commit | c48825251cf5950da9d618144c4db6c130e6c0cd (patch) | |
| tree | 2e8a163cfaddfdb78243f0ba501b1923e3d7d3be /include/linux | |
| parent | bc25cf508942c56810d4fb623ef27b56ccef7783 (diff) | |
PM: Add comment describing relationships between PM callbacks to pm.h
The UNIVERSAL_DEV_PM_OPS() macro is slightly misleading, because it
may suggest that it's a good idea to point runtime PM callback
pointers to the same routines as system suspend/resume callbacks
.suspend() and .resume(), which is not the case. For this reason,
add a comment to include/linux/pm.h, next to the definition of
UNIVERSAL_DEV_PM_OPS(), describing how device PM callbacks are
related to each other.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/pm.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/pm.h b/include/linux/pm.h index 73c610573a74..d6dd6f612b8d 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -320,6 +320,15 @@ const struct dev_pm_ops name = { \ /* * Use this for defining a set of PM operations to be used in all situations * (sustem suspend, hibernation or runtime PM). + * NOTE: In general, system suspend callbacks, .suspend() and .resume(), should + * be different from the corresponding runtime PM callbacks, .runtime_suspend(), + * and .runtime_resume(), because .runtime_suspend() always works on an already + * quiescent device, while .suspend() should assume that the device may be doing + * something when it is called (it should ensure that the device will be + * quiescent after it has returned). Therefore it's better to point the "late" + * suspend and "early" resume callback pointers, .suspend_late() and + * .resume_early(), to the same routines as .runtime_suspend() and + * .runtime_resume(), respectively (and analogously for hibernation). */ #define UNIVERSAL_DEV_PM_OPS(name, suspend_fn, resume_fn, idle_fn) \ const struct dev_pm_ops name = { \ |