From: Wolfram Sang <wsa@the-dreams.de>
To: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Alexandre Courbot <gnurou@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Vignesh R <vigneshr@ti.com>, Yong Li <yong.b.li@intel.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Peter Rosin <peda@axentia.se>,
linux-i2c <linux-i2c@vger.kernel.org>,
linux-gpio <linux-gpio@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/4] gpio: fix an incorrect lockdep warning
Date: Sat, 24 Sep 2016 10:56:04 +0200 [thread overview]
Message-ID: <20160924085604.GC1434@katana> (raw)
In-Reply-To: <1474041765-17818-1-git-send-email-bgolaszewski@baylibre.com>
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On Fri, Sep 16, 2016 at 06:02:41PM +0200, Bartosz Golaszewski wrote:
> If an I2C GPIO multiplexer is driven by a GPIO provided by an expander
> when there's a second expander using the same device driver on one of
> the I2C bus segments, lockdep prints a deadlock warning when trying to
> set the direction or the value of the GPIOs provided by the second
> expander.
>
> This series exports an already existing function from i2c-core as
> public API and reuses it in pca953x to pass a correct lock subclass
> to lockdep.
>
> Note: if this series gets merged, I'll prepare follow-up patches for
> other expanders for which a similar problem could potentially occur.
>
> Tested with the following setup:
>
> ------- --------- Bus segment 1 | |
> | | | |--------------- Devices
> | | SCL/SDA | | | |
> | Linux |-----------| I2C MUX | - - - - -
> | | | | | Bus segment 2
> | | | | |-------------------
> ------- | --------- |
> | | - - - - -
> ------------ | MUX GPIO | |
> | | | Devices
> | GPIO | | | |
> | Expander 1 |---- - - - - -
> | | |
> ------------ | SCL/SDA
> |
> ------------
> | |
> | GPIO |
> | Expander 2 |
> | |
> ------------
>
> where expander 1 is a pca9534 and expander 2 is a pca9535.
>
> v1 -> v2:
> - added patches 1/4, 2/4 & 3/4
> - used i2c_adapter_depth() in patch 4/4 in order to detect multiple
> adapter nesting
>
> Bartosz Golaszewski (4):
> i2c: export i2c_adapter_depth()
> lockdep: make MAX_LOCKDEP_SUBCLASSES unconditionally visible
> i2c: add a warning to i2c_adapter_depth()
> gpio: pca953x: fix an incorrect lockdep warning
Applied to for-next, thanks!
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prev parent reply other threads:[~2016-09-24 8:56 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-16 16:02 [PATCH v2 0/4] gpio: fix an incorrect lockdep warning Bartosz Golaszewski
2016-09-16 16:02 ` [PATCH v2 1/4] i2c: export i2c_adapter_depth() Bartosz Golaszewski
2016-09-16 16:02 ` [PATCH v2 2/4] lockdep: make MAX_LOCKDEP_SUBCLASSES unconditionally visible Bartosz Golaszewski
2016-09-16 16:02 ` [PATCH v2 3/4] i2c: add a warning to i2c_adapter_depth() Bartosz Golaszewski
2016-09-16 16:02 ` [PATCH v2 4/4] gpio: pca953x: fix an incorrect lockdep warning Bartosz Golaszewski
2016-09-21 5:45 ` Wolfram Sang
2016-09-23 8:10 ` Linus Walleij
2016-09-24 8:55 ` Wolfram Sang
2016-09-24 9:15 ` Wolfram Sang
2016-09-24 14:26 ` Geert Uytterhoeven
2016-09-16 17:26 ` [PATCH v2 0/4] gpio: " Wolfram Sang
2016-09-16 17:45 ` Peter Rosin
2016-09-16 17:58 ` Wolfram Sang
2016-09-18 8:52 ` Peter Rosin
2016-09-18 19:43 ` Bartosz Golaszewski
2016-09-18 19:45 ` Bartosz Golaszewski
2016-09-19 8:01 ` Peter Rosin
2016-09-19 8:14 ` Peter Zijlstra
2016-09-19 8:48 ` Peter Rosin
2016-09-19 9:03 ` Peter Zijlstra
2016-09-20 8:48 ` Peter Rosin
2016-09-20 10:07 ` Bartosz Golaszewski
2016-09-20 10:28 ` Peter Zijlstra
2016-09-20 10:48 ` Peter Rosin
2016-09-20 11:30 ` Geert Uytterhoeven
2016-09-20 12:32 ` Bartosz Golaszewski
2016-09-20 15:33 ` Thomas Gleixner
2016-09-21 9:47 ` Peter Rosin
2016-09-17 1:19 ` Peter Zijlstra
2016-09-17 10:18 ` Wolfram Sang
2016-09-17 18:59 ` Bartosz Golaszewski
2016-09-24 8:56 ` Wolfram Sang [this message]
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