On Mon, Jul 28, 2014 at 06:52:48PM +0200, Luis R. Rodriguez wrote: > On Mon, Jul 28, 2014 at 03:46:32PM +0000, Yuval Mintz wrote: > > > Subject: Re: [PATCH 1/3] driver core: enable drivers to use deferred probe from > > > init > > > > > > On Mon, Jul 28, 2014 at 03:12:11PM +0000, Yuval Mintz wrote: > > > > Perhaps this is a silly question, but what guarantees that the > > > > deferred probe list will actually be triggered, e.g., in case the > > > > delayed device is the last device in the system? > > > > > > The dev->init_delayed_probe is used to ensure that we'd add the device to the > > > deferred probe list once making this a per device thing if the driver has the field > > > delay_probe set to true. This technically also allows this to be a per device thing > > > so with some more work we could enable drivers to only enable this for specific > > > devices but at this point this did not seem required. > > > > Sorry for not being clear, but I didn't meant 'what guarantees that the device > > will be added to the deferred probe', but rather what guarantees that the > > deferred workqueue will be scheduled. > > > > To the best of my knowledge the deferring mechanism works only if one device > > is dependent upon another, e.g., for Multi-function devices where one device > > probe is dependent upon the others - which are soon-to-be probed. > > The workqueue will be kicked when driver_deferred_probe_trigger() gets > poked, we do that in the late_initcall(deferred_probe_initcall), it > also gets flushed there with a flush_workqueue(deferred_wq). But come to think of it that will work well for devices already plugged in so indeed I think that driver_deferred_probe_add() needs a check added for for if (!driver_deferred_probe_enable) then we have to driver_deferred_probe_trigger(). The driver_deferred_probe_enable is set to false upon init, but later on late init it gets set to true so with that check we'd only generate the trigger after late init call. I can fold that in the v2. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
