On 2015/8/17 16:46, Arend van Spriel wrote: > + Rafael > > On 08/17/2015 09:29 AM, Johannes Berg wrote: >> On Mon, 2015-08-17 at 09:48 +0800, Fu, Zhonghui wrote: >>> >>> The suspend/resume timing of wiphy device and related devices will be >>> ensured by their parent/child relationship. So, enabling wiphy device >>> to suspend/resume asynchronously does not change any dependency. It >>> can only take advantage of multicore and improve system >>> suspend/resume speed. >>> >> >> You're going to have to explain that to me, because I don't see that. >> All I see is that when looking at a device, if async is possible, it >> gets added to an async work, and if async is not possible then it gets >> done immediately. Even putting aside the question of whether or not >> async is ordered or not (I don't know), if the wiphy is async and the >> PCI (or other bus) device isn't, then it seems they could get handled >> out of order, no? Or is there some magic code somewhere that I'm >> missing that explicitly waits for the async of the parent/child >> relationship? > > This patch got me worried as well. Can't find the magic either. Maybe Rafael can give some hints here. "dpm_wait_for_children" function will be invoked in "__device_suspend", "__device_suspend_late", and "__device_suspend_noirq" functions to synchronize the child relationship. "dpm_wait" function will be invoked in "device_resume_noirq", "device_resume_early", and "device_resume" functions to synchronize the parent relationship. If two devices have parent/child relationship, but different suspend/resume mode(sync or async), this will have no impact to PM timing order between them. Because all devices will use "__device_suspend", "__device_suspend_late" ... functions to complete their PM transition. Thanks, Zhonghui > > Regards, > Arend > >> johannes >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-wireless" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
