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From: Kevin Hilman <khilman@ti.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Greg Kroah-Hartman <greg@kroah.com>, Dilan Lee <dilee@nvidia.com>,
	Mark Brown <broonie@opensource.wolfsonmicro.com>,
	Manjunath GKondaiah <manjunath.gkondaiah@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: [RFC PATCH v3] drivercore: Add driver probe deferral mechanism
Date: Mon, 03 Oct 2011 16:02:57 -0700	[thread overview]
Message-ID: <87d3edllum.fsf@ti.com> (raw)
In-Reply-To: <20110922184614.25419.84606.stgit@ponder> (Grant Likely's message of "Thu, 22 Sep 2011 12:51:23 -0600")

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.

Kevin

WARNING: multiple messages have this Message-ID (diff)
From: khilman@ti.com (Kevin Hilman)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v3] drivercore: Add driver probe deferral mechanism
Date: Mon, 03 Oct 2011 16:02:57 -0700	[thread overview]
Message-ID: <87d3edllum.fsf@ti.com> (raw)
In-Reply-To: <20110922184614.25419.84606.stgit@ponder> (Grant Likely's message of "Thu, 22 Sep 2011 12:51:23 -0600")

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.

Kevin

  parent reply	other threads:[~2011-10-03 23:03 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-22 18:51 [RFC PATCH v3] drivercore: Add driver probe deferral mechanism Grant Likely
2011-09-22 18:51 ` Grant Likely
2011-09-22 18:58 ` Joe Perches
2011-09-22 18:58   ` Joe Perches
2011-09-22 19:28 ` David Daney
2011-09-22 20:29 ` Alan Cox
2011-09-22 20:29   ` Alan Cox
2011-09-22 21:19   ` Grant Likely
2011-09-22 21:19     ` Grant Likely
2011-09-23 17:50     ` Valdis.Kletnieks
2011-09-23 17:50       ` Valdis.Kletnieks at vt.edu
2011-09-23 23:18       ` Grant Likely
2011-09-23 23:18         ` Grant Likely
2011-09-22 21:19   ` David Daney
2011-09-22 22:47     ` Alan Cox
2011-09-22 22:47       ` Alan Cox
2011-09-23  5:02       ` Grant Likely
2011-09-23  5:02         ` Grant Likely
2011-09-23 16:55       ` David Daney
2011-09-23 16:55         ` David Daney
2011-09-26 14:16 ` Mark Brown
2011-09-26 14:16   ` Mark Brown
2011-09-26 15:12   ` Russell King - ARM Linux
2011-09-26 15:12     ` Russell King - ARM Linux
2011-09-26 15:26     ` Mark Brown
2011-09-26 15:26       ` Mark Brown
2011-09-26 15:48       ` Grant Likely
2011-09-26 15:48         ` Grant Likely
2011-09-27 13:50         ` Arnd Bergmann
2011-09-27 13:50           ` Arnd Bergmann
2011-09-27 21:08           ` Grant Likely
2011-09-27 21:08             ` Grant Likely
2011-09-27 22:13             ` Mark Brown
2011-09-27 22:13               ` Mark Brown
2011-09-28 13:04               ` Arnd Bergmann
2011-09-28 13:04                 ` Arnd Bergmann
2011-09-28 13:20                 ` Mark Brown
2011-09-28 13:20                   ` Mark Brown
2011-09-28 23:14               ` Grant Likely
2011-09-28 23:14                 ` Grant Likely
2011-09-29 11:00                 ` Mark Brown
2011-09-29 11:00                   ` Mark Brown
2011-10-03 23:02 ` Kevin Hilman [this message]
2011-10-03 23:02   ` Kevin Hilman
2011-10-04 15:52   ` Grant Likely
2011-10-04 15:52     ` Grant Likely
2011-10-04 14:51 ` G, Manjunath Kondaiah
2011-10-04 14:51   ` G, Manjunath Kondaiah
2011-10-04 14:51   ` G, Manjunath Kondaiah
2011-10-04 15:58   ` Grant Likely
2011-10-04 15:58     ` Grant Likely
2011-10-04 15:58     ` Grant Likely
2011-10-04 18:35     ` G, Manjunath Kondaiah
2011-10-04 18:35       ` G, Manjunath Kondaiah
2011-10-04 23:35       ` Grant Likely
2011-10-04 23:35         ` Grant Likely
2011-10-07  3:31         ` G, Manjunath Kondaiah
2011-10-07  3:31           ` G, Manjunath Kondaiah
2011-10-11 20:47 ` Andrew Morton
2011-10-11 20:47   ` Andrew Morton
2011-10-11 21:07   ` David Daney
2011-10-13  4:19     ` Grant Likely
2011-10-13  4:19       ` Grant Likely

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