Messages in this thread | | | Date | Wed, 17 Jun 2015 11:10:09 -0600 | From | Sagar Dharia <> | Subject | Re: [PATCH 1/3] SLIMbus: Device management on SLIMbus |
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On 6/17/2015 5:45 AM, Mark Brown wrote: > On Tue, Jun 16, 2015 at 09:22:31AM -0600, Sagar Dharia wrote: >> On 6/15/2015 4:54 AM, Mark Brown wrote: >>> On Sat, Jun 13, 2015 at 11:49:16PM -0600, Sagar Dharia wrote: >>>> +void slim_ctrl_add_boarddevs(struct slim_controller *ctrl) >>>> +{ >>> Why are these operations split? >> Some slaves may choose to do expensive operations in their probes (or wait >> for logical address assignment). That will delay/block controller >> registration and further HW initialization of the controller. >> I did not see any downside/side-effect in splitting them. I am open however >> to have them combined if that's the preferred way. > How does this resolve the issue? As far as I can see it just shuffles > it around so any delay happens later (and possibly not at a convenient > time), possibly not helping if there's multiple controllers. If devices > are doing excessively expensive things in their probe that seems like > something that we should fix in the drivers. For LA assignment > shouldn't we be addressing that by having a callback when the LA is > assigned? That will avoid single threading effects and is more like the > pattern for other buses. Slimbus isn't particularly unique in this > regard. I agree that using the 'device_up' callback (it's called when the device has LA assignment) will make sure slaves can keep their probes non-blocking. I was just trying to accommodate that blocking call by slaves and did not realize the downside you now mentioned about multiple-controllers I will combine these in next patchset. Thanks Sagar > > Greg, the LA assignment thing here is an example of the issue is an > example of the pattern I raised a while ago (but never got round to > coding up handling of) where we have devices on an enumerable bus with > static registrations. LA assignment is the end of the hotplug process > for a Slimbus device but most devices will need something doing to power > them up so they enumerate.
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