Messages in this thread | | | From | Grant Likely <> | Date | Tue, 4 Oct 2011 09:52:52 -0600 | Subject | Re: [RFC PATCH v3] drivercore: Add driver probe deferral mechanism |
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On Mon, Oct 3, 2011 at 5:02 PM, Kevin Hilman <khilman@ti.com> wrote: > Grant Likely <grant.likely@secretlab.ca> writes: > >> Allow drivers to report at probe time that they cannot get all the resources >> required by the device, and should be retried at a later time. >> >> This should completely solve the problem of getting devices >> initialized in the right order. Right now this is mostly handled by >> mucking about with initcall ordering which is a complete hack, and >> doesn't even remotely handle the case where device drivers are in >> modules. This approach completely sidesteps the issues by allowing >> driver registration to occur in any order, and any driver can request >> to be retried after a few more other drivers get probed. > > This is great work, thanks! > > For the TODO list: > > While the proposed patch should solve probe order dependencies, I don't > think it will solve the suspend/resume ordering dependencies, which are > typically the same. > > Currenly suspend/resume order is based on the order devices are *added* > (device_add() -> device_pm_add() -> device added to dpm_list), so > unfortunately, deferring probe isn't going to affect suspend/resume > ordering. > > Extending this to also address suspend/resume ordering by also changing > when the device is added to the dpm_list (or possibly creating another > list) should probably be explored as well.
Hmm, yes, I think this is worth exploring. It doesn't help with runtime pm dependencies, but it has the potential to make PM just work if the list order is updated each time a device is successfully bound to a driver. Manjunath, can you investigate what it would take to do this? (after getting the core deferral patch finalized; I don't want to block that work)?
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