From: khilman@linaro•org (Kevin Hilman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 1/9] i2c: prepare runtime PM support for I2C client devices
Date: Fri, 13 Sep 2013 07:30:55 -0700 [thread overview]
Message-ID: <87bo3whjz4.fsf@linaro.org> (raw)
In-Reply-To: <20130913065434.GZ7393@intel.com> (Mika Westerberg's message of "Fri, 13 Sep 2013 09:54:34 +0300")
Mika Westerberg <mika.westerberg@linux•intel.com> writes:
> On Thu, Sep 12, 2013 at 02:34:21PM -0700, Kevin Hilman wrote:
>> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
>> > index f32ca29..44374b4 100644
>> > --- a/drivers/i2c/i2c-core.c
>> > +++ b/drivers/i2c/i2c-core.c
>> > @@ -248,11 +248,30 @@ static int i2c_device_probe(struct device *dev)
>> > client->flags & I2C_CLIENT_WAKE);
>> > dev_dbg(dev, "probe\n");
>> >
>> > + /* Make sure the adapter is active */
>> > + pm_runtime_get_sync(&client->adapter->dev);
>> > +
>> > + /*
>> > + * Enable runtime PM for the client device. If the client wants to
>> > + * participate on runtime PM it should call pm_runtime_put() in its
>> > + * probe() callback.
>> > + */
>> > + pm_runtime_get_noresume(&client->dev);
>> > + pm_runtime_set_active(&client->dev);
>>
>> Why the set_active here?
>>
>> For hardware that is disabled/powered-off on startup, there will now be
>> a mismatch between the hardware state an the RPM core state.
>
> The call to pm_runtime_get_noresume() should make sure that the device is
> in active state (at least in state where it can access the bus) if I'm
> understanding this right.
No, after _get_noresume(), nothing happens to the hardware. It simply
increments the usecount. From pm_runtime.h:
static inline void pm_runtime_get_noresume(struct device *dev)
{
atomic_inc(&dev->power.usage_count);
}
So after the _get_noresume() and _set_active() you're very likely to
have a disconnect between the hardware state and what state RPM thinks
the hardware is in.
Kevin
next prev parent reply other threads:[~2013-09-13 14:30 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-11 15:32 [PATCH v2 0/9] runtime PM support for I2C and SPI client devices Mika Westerberg
2013-09-11 15:32 ` [PATCH v2 1/9] i2c: prepare runtime PM support for I2C " Mika Westerberg
2013-09-12 21:34 ` Kevin Hilman
2013-09-12 21:40 ` Kevin Hilman
[not found] ` <20130913065434.GZ7393@intel.com>
2013-09-13 9:59 ` Mark Brown
[not found] ` <20130913101611.GA7393@intel.com>
2013-09-13 10:31 ` Mark Brown
[not found] ` <20130913115035.GB7393@intel.com>
2013-09-13 12:10 ` Mark Brown
2013-09-13 14:30 ` Kevin Hilman [this message]
[not found] ` <20130913145022.GC7393@intel.com>
[not found] ` <20130913173149.GE7393@intel.com>
2013-09-13 21:10 ` Kevin Hilman
[not found] ` <20130915064139.GJ7393@intel.com>
2013-09-15 12:47 ` Mark Brown
[not found] ` <20130915132823.GL7393@intel.com>
2013-09-16 10:12 ` Mark Brown
[not found] ` <20130916143811.GP7393@intel.com>
2013-09-16 14:46 ` Graeme Gregory
2013-09-13 15:14 ` Sylwester Nawrocki
[not found] ` <20130913154013.GD7393@intel.com>
2013-09-15 13:48 ` Sylwester Nawrocki
[not found] ` <20130916084708.GN7393@intel.com>
2013-09-16 19:07 ` Rafael J. Wysocki
2013-09-16 23:31 ` Mark Brown
2013-09-17 1:25 ` Rafael J. Wysocki
2013-09-17 10:48 ` Mark Brown
[not found] ` <20130917110021.GU7393@intel.com>
2013-09-17 21:38 ` Rafael J. Wysocki
2013-09-17 11:07 ` Sylwester Nawrocki
2013-09-12 22:06 ` Sylwester Nawrocki
2013-09-13 1:14 ` Aaron Lu
2013-09-13 10:02 ` Mark Brown
2013-09-11 15:32 ` [PATCH v2 2/9] i2c: attach/detach I2C client device to the ACPI power domain Mika Westerberg
2013-09-11 15:32 ` [PATCH v2 3/9] Input: misc - convert existing I2C client drivers to use I2C core runtime PM Mika Westerberg
2013-09-11 15:32 ` [PATCH v2 4/9] [media] s5p-tv: convert " Mika Westerberg
2013-09-11 15:32 ` [PATCH v2 5/9] drivers/misc: convert existing I2C clients driver " Mika Westerberg
2013-09-12 21:29 ` Greg Kroah-Hartman
2013-09-11 15:32 ` [PATCH v2 6/9] mfd: wm8994: convert " Mika Westerberg
2013-09-11 16:12 ` Samuel Ortiz
[not found] ` <20130912092447.GJ7393@intel.com>
2013-09-12 9:28 ` Samuel Ortiz
2013-09-11 15:32 ` [PATCH v2 7/9] ASoC: codecs: convert existing I2C client drivers " Mika Westerberg
2013-09-11 15:44 ` Mark Brown
2013-09-11 15:32 ` [PATCH v2 8/9] spi: prepare runtime PM support for SPI devices Mika Westerberg
2013-09-11 15:51 ` Mark Brown
[not found] ` <20130912092743.GK7393@intel.com>
2013-09-12 9:31 ` Mark Brown
[not found] ` <20130912094302.GM7393@intel.com>
2013-09-12 11:04 ` Rafael J. Wysocki
2013-09-12 11:04 ` Wolfram Sang
2013-09-11 15:32 ` [PATCH v2 9/9] spi: attach/detach SPI device to the ACPI power domain Mika Westerberg
2013-09-11 15:51 ` Mark Brown
2013-09-11 15:53 ` [PATCH v2 0/9] runtime PM support for I2C and SPI client devices Mark Brown
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