On Thursday, July 28, 2016 05:28:31 PM Lukas Wunner wrote: > On Thu, Jul 28, 2016 at 02:30:31AM +0200, Rafael J. Wysocki wrote: > > On Monday, July 25, 2016 12:48:32 AM Lukas Wunner wrote: > > > On Thu, Jul 21, 2016 at 02:25:15AM +0200, Rafael J. Wysocki wrote: > > > > On Thursday, July 21, 2016 01:25:53 AM Lukas Wunner wrote: > > > > > I guess I could amend portdrv to return -EPROBE_DEFER on Macs if > > > > > no driver is bound to the NHI. Doesn't feel pretty to me though. > > > > > > > > > > Ultimately this seems to be the same issue as with calling > > > > > dev_pm_domain_set() for a bound device. Perhaps device_link_add() > > > > > can likewise be allowed if a runtime PM ref is held for the devices > > > > > and the call happens under lock_system_sleep()? > > > > > > > > No, the whole synchronization scheme in the links code would have had to be > > > > changed for that to really work. > > > > > > > > And it really is about what is needed (at least in principle) to run your > > > > device. If you think you need device X with a driver to handle device Y > > > > correctly, then either you need it all the time, from probe to remove, or > > > > you just don't really need it at all. > > > > > > Real life isn't as simple as that. > > > > > > In this case, we have consumers (hotplug ports) which are doing fine > > > if the driver for the supplier (NHI) is not loaded. But once it loads, > > > the links must be in place. > > > > Hmm. > > > > What if it is not loaded and the system suspends. Will everything work > > as expected after the subsequent resume? > > The short answer is yes. OK I think it's possible to add a link flag to address this case. Namely, if that flag is passed to device_link_add(), the link will be added in the DEVICE_LINK_ACTIVE state right away, but that will need to be synchronized against all possible transitions of the consumer device (at least). It's better to do that in a separate patch for this reason IMO. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
