On 08/06/2013 03:22 PM, Alan Stern wrote: > On Tue, 6 Aug 2013, Shuah Khan wrote: > >> With the dev_pm_ops model, drivers have to provide interfaces for each >> one of these states. > > No, they don't. They can leave out interfaces if they want.
Yes. Agreed. There is no need to provide each and every interface. Only the ones driver wishes to handle. > >> In this case, there will be a conflict since >> pm_op() treats this state as freeze where as the driver wants to do >> treat it as a suspend/hibernate. In the case of legacy pm_ops, state is >> passed in as a parameter and driver could take special action if need >> be, based on the state, however in dev_pm_ops model, state is not passed >> in. Instead it is handled with state specific pm_ops interfaces. >> >> For example, if this driver were to be converted to dev_pm_ops, it would >> require a freeze interface which will call sl811h_bus_suspend(). Once >> that is done, PM_EVENT_PRETHAW will be mapped to freeze() ops and >> sl811h_bus_suspend() will be called instead of port_power(sl811, 0); >> >> What I am getting at is, there is no provision to handle the special >> case for PM_EVENT_PRETHAW like in the case of this driver when using >> dev_pm_ops. > > Okay. So what? > I am exploring to see if there is a deficiency in dev_pm_ops infrastructure that needs addressing. Based on this example, there is a need for a way to allow drivers that want to do something state specific that is different from the defined framework if need be. -- Shuah Shuah Khan, Linux Kernel Developer - Open Source Group Samsung Research America (Silicon Valley) [email protected] | (970) 672-0658 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
