From: Mark Brown <broonie@opensource.wolfsonmicro.com> To: Arnd Bergmann <arnd@arndb.de> Cc: Grant Likely <grant.likely@secretlab.ca>, Russell King - ARM Linux <linux@arm.linux.org.uk>, Greg Kroah-Hartman <greg@kroah.com>, linux-kernel@vger.kernel.org, Manjunath GKondaiah <manjunath.gkondaiah@linaro.org>, Dilan Lee <dilee@nvidia.com>, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH v3] drivercore: Add driver probe deferral mechanism Date: Wed, 28 Sep 2011 14:20:42 +0100 [thread overview] Message-ID: <20110928132042.GL3279@opensource.wolfsonmicro.com> (raw) In-Reply-To: <201109281504.34560.arnd@arndb.de> On Wed, Sep 28, 2011 at 03:04:34PM +0200, Arnd Bergmann wrote: > On Wednesday 28 September 2011, Mark Brown wrote: > > Note that I'm not sure this answers the issue I was raising - the issue > > isn't that the caller doesn't know what the error code means, the issue > > is that in some cases the driver needs to take a decision about what > > failure to get a resource means. Does it mean that the driver can work > > fine and be slightly less featureful or should it cause a deferral? > Can you think of cases where this information cannot be put into the > device tree or platform_data? If a board provides an optional feature, > I think that should be a property of the device that the driver gets, > so it can return an error when that feature is not around, or continue > when it knows that the feature will never become available. Not off the top of my head, most of the cases I'm aware of were cases where the supply is mandatory but soft control is optional so don't need to make this decision in the driver at all. In the MMC case I didn't push this as working with the people concerned was extremely painful.
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From: broonie@opensource.wolfsonmicro.com (Mark Brown) To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH v3] drivercore: Add driver probe deferral mechanism Date: Wed, 28 Sep 2011 14:20:42 +0100 [thread overview] Message-ID: <20110928132042.GL3279@opensource.wolfsonmicro.com> (raw) In-Reply-To: <201109281504.34560.arnd@arndb.de> On Wed, Sep 28, 2011 at 03:04:34PM +0200, Arnd Bergmann wrote: > On Wednesday 28 September 2011, Mark Brown wrote: > > Note that I'm not sure this answers the issue I was raising - the issue > > isn't that the caller doesn't know what the error code means, the issue > > is that in some cases the driver needs to take a decision about what > > failure to get a resource means. Does it mean that the driver can work > > fine and be slightly less featureful or should it cause a deferral? > Can you think of cases where this information cannot be put into the > device tree or platform_data? If a board provides an optional feature, > I think that should be a property of the device that the driver gets, > so it can return an error when that feature is not around, or continue > when it knows that the feature will never become available. Not off the top of my head, most of the cases I'm aware of were cases where the supply is mandatory but soft control is optional so don't need to make this decision in the driver at all. In the MMC case I didn't push this as working with the people concerned was extremely painful.
next prev parent reply other threads:[~2011-09-28 13:20 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 [this message] 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 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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