From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Peter Rosin <peda@axentia.se>
Cc: Wolfram Sang <wsa@the-dreams.de>,
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>,
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: Sun, 18 Sep 2016 21:43:10 +0200 [thread overview]
Message-ID: <CAMpxmJUX8wszxhkoOyuqPeC8xgBjLXFRSWDSa0cOrJ92dUYX1g@mail.gmail.com> (raw)
In-Reply-To: <587cdb60-d7fe-3ab2-b635-02c5072e102e@axentia.se>
2016-09-18 10:52 GMT+02:00 Peter Rosin <peda@axentia.se>:
> On 2016-09-16 19:58, Wolfram Sang wrote:
>>
>> Same here. And if it prevents us from false positive lockdep reports, I
>> am all for fixing it.
>
> Except it doesn't, when I think some more about it...
>
> If you have two gpio-expanders on the same depth but on different i2c
> branches you still end up with a splat if one is used to control a mux
> to reach the other.
>
> The only way to solve it for good, that I see, is to have every instance
> of the gpio-expander mutex in its own class. That might lead to many
> lockdep classes but then again, how many gpio expanders could there be
> in a system? A dozen or two seems extreme, so maybe that is the correct
> approach anyway?
Wouldn't it be enough to have a separate class for every base (as in:
not having any parent adapters) i2c adapter?
Best regards,
Bartosz Golaszewski
next prev parent reply other threads:[~2016-09-18 19:43 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 [this message]
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
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