From: Peter Rosin <peda@lysator.liu.se>
To: Lars-Peter Clausen <lars@metafoo.de>, Wolfram Sang <wsa@the-dreams.de>
Cc: Peter Rosin <peda@axentia.se>, Rob Herring <robh+dt@kernel.org>,
Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
Peter Korsgaard <peter.korsgaard@barco.com>,
Guenter Roeck <linux@roeck-us.net>,
linux-i2c@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/10] i2c: pca954x: get rid of the i2c deadlock workaround
Date: Mon, 04 Jan 2016 16:45:36 +0100 [thread overview]
Message-ID: <568A93A0.5030109@lysator.liu.se> (raw)
In-Reply-To: <568A8D87.8020201@metafoo.de>
On 2016-01-04 16:19, Lars-Peter Clausen wrote:
> On 01/04/2016 04:10 PM, Peter Rosin wrote:
>> From: Peter Rosin <peda@axentia.se>
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
>
> It would be quite good if the commit messaged said why it is now safe to
> remove the workaround.
Right, hmm, the two last patches seemed obvious at the time I wrote them,
but now I see a problem.
E.g. if two pca954x devices that depends on being idle when client devices
are not accessed happen to sit on the same bus (perhaps because the muxes
are used to hide a bunch of identical devices), it is indeed not safe to
make this change.
Thanks for making my think, and consider 9/10 and 10/10 dropped.
Cheers,
Peter
prev parent reply other threads:[~2016-01-04 15:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-04 15:10 [PATCH 00/10] i2c mux cleanup and locking update Peter Rosin
2016-01-04 15:10 ` [PATCH 01/10] i2c-mux: add common core data for every mux instance Peter Rosin
2016-01-04 15:37 ` Guenter Roeck
2016-01-05 9:05 ` Peter Rosin
[not found] ` <1451920215-29167-2-git-send-email-peda-SamgB31n2u5IcsJQ0EH25Q@public.gmane.org>
2016-01-04 15:46 ` kbuild test robot
2016-01-04 15:49 ` kbuild test robot
2016-01-04 15:10 ` [PATCH 02/10] i2c-mux: move select and deselect ops to i2c_mux_core Peter Rosin
2016-01-04 15:54 ` kbuild test robot
[not found] ` <1451920215-29167-3-git-send-email-peda-SamgB31n2u5IcsJQ0EH25Q@public.gmane.org>
2016-01-04 15:56 ` kbuild test robot
2016-01-04 16:01 ` kbuild test robot
2016-01-04 16:02 ` kbuild test robot
2016-01-04 15:10 ` [PATCH 03/10] i2c-mux: move the slave side adapter management " Peter Rosin
2016-01-04 16:02 ` kbuild test robot
2016-01-04 15:10 ` [PATCH 04/10] i2c-mux: remove the mux dev pointer from the mux per channel data Peter Rosin
2016-01-04 15:10 ` [PATCH 05/10] i2c-mux: pinctrl: get rid of the driver private struct device pointer Peter Rosin
2016-01-04 15:10 ` [PATCH 06/10] i2c: allow adapter drivers to override the adapter locking Peter Rosin
[not found] ` <1451920215-29167-1-git-send-email-peda-SamgB31n2u5IcsJQ0EH25Q@public.gmane.org>
2016-01-04 15:10 ` [PATCH 07/10] i2c: muxes always lock the parent adapter Peter Rosin
2016-01-04 15:10 ` [PATCH 08/10] i2c-mux: relax locking of the top i2c adapter during i2c controlled muxing Peter Rosin
2016-01-04 15:10 ` [PATCH 09/10] i2c: pca9541: get rid of the i2c deadlock workaround Peter Rosin
2016-01-04 15:10 ` [PATCH 10/10] i2c: pca954x: " Peter Rosin
2016-01-04 15:19 ` Lars-Peter Clausen
2016-01-04 15:45 ` Peter Rosin [this message]
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