Re: [PATCH 1/3] driver core: Add API to wait for deferred probe tocomplete during init

From: Saravana Kannan
Date: Thu May 09 2013 - 12:52:40 EST


On 05/09/2013 04:50 AM, Grant Likely wrote:
On Thu, May 9, 2013 at 11:07 AM, Ming Lei <tom.leiming@xxxxxxxxx> wrote:
On Thu, May 9, 2013 at 1:18 PM, Saravana Kannan <skannan@xxxxxxxxxxxxxx> wrote:

The most obvious fallback of using late_initcall_sync() also doesn't work
since the deferred probing work initated during late_initcall() is done in
a workqueue. So, frameworks that want to wait for all devices to finish
probing during init will now have to wait for the deferred workqueue to
finish it's work. This patch adds a wait_for_init_deferred_probe_done() API

flush_workqueue() has been added in deferred_probe_initcall(), so looks it
should be OK for your problem, doesn't it?

It looks like Saravana is using a kernel that already does that based
on object bb5645e from the diff. So if he is still having problem,
then there is probably another deferred probe that is triggered after
the deferred probe lateinitcall is executed. It would be good to know
what driver is getting deferred past clearing the queue. Or has this
been rebased from an earlier kernel? It may no longer be necessary.

Sorry, it was mindless rebase late at night. I missed the addition of the flush_workqueue(). That takes care of my immediate needs. Sorry for wasting your time.

But the other patches to move clock and regulator calls to late_init_sync should still be necessary. Right? Or are we going to depend on the Makefile ordering to determine the order of the lateinit calls? (I would rather not).

But the rest of the discussion is still interesting and relevant and something I would like to see resolved too. I'll reply to that part of the discussion in one of the later emails.

Thanks,
Saravana

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/