Re: [PATCHv3 0/4] drivers/base: bugfix for supplier<-consumer ordering in device_kset

On Wednesday, July 4, 2018 4:47:07 AM CEST Pingfan Liu wrote:

On Tue, Jul 3, 2018 at 10:36 PM Rafael J. Wysocki [off-list ref] wrote:

quoted

On Tuesday, July 3, 2018 8:50:38 AM CEST Pingfan Liu wrote:

quoted

commit 52cdbdd49853 ("driver core: correct device's shutdown order")
places an assumption of supplier<-consumer order on the process of probe.
But it turns out to break down the parent <- child order in some scene.
E.g in pci, a bridge is enabled by pci core, and behind it, the devices
have been probed. Then comes the bridge's module, which enables extra
feature(such as hotplug) on this bridge.

So what *exactly* does happen in that case?

I saw the  shpc_probe() is called on the bridge, although the probing
failed on that bare-metal. But if it success, then it will enable the
hotplug feature on the bridge.

I don't understand what you are saying here, sorry.

device_reorder_to_tail() walks the entire device hierarchy below the target
and moves all of the children in there *after* their parents.

How can it break "the parent <- child order" then?

Thanks,
Rafael