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authorRafael J. Wysocki <rjw@sisk.pl>2011-04-29 00:35:50 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-04-29 00:35:50 +0200
commit4d27e9dcff00a6425d779b065ec8892e4f391661 (patch)
tree6602f1dcfad3e3065a1c081cf89f2d020976600d /include/linux/sys.h
parentfafc9929c668f8bae6dd1f109f33a86d2cb3c460 (diff)
PM: Make power domain callbacks take precedence over subsystem ones
Change the PM core's behavior related to power domains in such a way that, if a power domain is defined for a given device, its callbacks will be executed instead of and not in addition to the device subsystem's PM callbacks. The idea behind the initial implementation of power domains handling by the PM core was that power domain callbacks would be executed in addition to subsystem callbacks, so that it would be possible to extend the subsystem callbacks by using power domains. It turns out, however, that this wouldn't be really convenient in some important situations. For example, there are systems in which power can only be removed from entire power domains. On those systems it is not desirable to execute device drivers' PM callbacks until it is known that power is going to be removed from the devices in question, which means that they should be executed by power domain callbacks rather then by subsystem (e.g. bus type) PM callbacks, because subsystems generally have no information about what devices belong to which power domain. Thus, for instance, if the bus type in question is the platform bus type, its PM callbacks generally should not be called in addition to power domain callbacks, because they run device drivers' callbacks unconditionally if defined. While in principle the default subsystem PM callbacks, or a subset of them, may be replaced with different functions, it doesn't seem correct to do so, because that would change the subsystem's behavior with respect to all devices in the system, regardless of whether or not they belong to any power domains. Thus, the only remaining option is to make power domain callbacks take precedence over subsystem callbacks. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Kevin Hilman <khilman@ti.com>
Diffstat (limited to 'include/linux/sys.h')
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