From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
To: Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
'Wolfram Sang' <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 01/13] i2c: bcm2835: Use devm_request_irq()
Date: Tue, 17 Dec 2013 19:21:05 -0700 [thread overview]
Message-ID: <52B10691.2010105@wwwdotorg.org> (raw)
In-Reply-To: <001d01cefaf3$b743e4c0$25cbae40$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
On 12/16/2013 11:46 PM, Jingoo Han wrote:
> Use devm_request_irq() to make cleanup paths simpler.
This may not be safe. The interrupt used by the I2C controllers on the
BCM2835 chip is shared between two controllers. In theory, you could run
into a condition where you're remove()ing the driver for one of the
controller (a), while the driver for controller (b) is still active, yet
the HW for controller (a) comes along and triggers an interrupt after
remove() but before the devm IRQ cleanup. That would result in the IRQ
handler for controller (a) executing after the remove() of the
associated device, which could cause a variety of problems.
You might be able to make this safe by explicitly clearing any IRQ
enable registers in remove(), but leaving the code using plain
request_irq() might be simpler.
next prev parent reply other threads:[~2013-12-18 2:21 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-17 6:45 [PATCH 00/13] i2c: Use devm_*() functions Jingoo Han
[not found] ` <001601cefaf3$940d0040$bc2700c0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-12-17 6:46 ` [PATCH 01/13] i2c: bcm2835: Use devm_request_irq() Jingoo Han
[not found] ` <001d01cefaf3$b743e4c0$25cbae40$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-12-18 2:21 ` Stephen Warren [this message]
[not found] ` <52B10691.2010105-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2013-12-18 4:15 ` Jingoo Han
[not found] ` <000601cefba7$d13450e0$739cf2a0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-01-04 21:06 ` Wolfram Sang
2013-12-17 6:48 ` [PATCH 02/13] i2c: gpio: Use devm_gpio_request() Jingoo Han
[not found] ` <001e01cefaf3$f8b520e0$ea1f62a0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-05-21 10:59 ` Wolfram Sang
2013-12-17 6:50 ` [PATCH 03/13] i2c: highlander: Use devm_*() functions Jingoo Han
2013-12-17 6:51 ` [PATCH 04/13] i2c: isch: Use devm_request_region() Jingoo Han
[not found] ` <002801cefaf4$69243d70$3b6cb850$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-12-17 7:53 ` Jean Delvare
[not found] ` <20131217085309.1459ea27-R0o5gVi9kd7kN2dkZ6Wm7A@public.gmane.org>
2013-12-18 1:42 ` Jingoo Han
[not found] ` <007401cefb92$6f521390$4df63ab0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-12-18 6:39 ` Jean Delvare
2013-12-18 1:48 ` [PATCH V2 " Jingoo Han
[not found] ` <007501cefb93$32ca0df0$985e29d0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-12-18 7:46 ` Jean Delvare
2014-01-04 21:23 ` Wolfram Sang
2013-12-17 6:53 ` [PATCH 05/13] i2c: mv64xxx: Use devm_request_irq() Jingoo Han
2013-12-17 6:54 ` [PATCH 06/13] i2c: pmcmsp: Use devm_*() functions Jingoo Han
2013-12-17 6:55 ` [PATCH 07/13] i2c: pnx: " Jingoo Han
[not found] ` <002b01cefaf4$fa737d40$ef5a77c0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-12-17 12:30 ` Roland Stigge
2014-01-04 21:07 ` Wolfram Sang
2014-01-06 2:39 ` [PATCH V2 " Jingoo Han
[not found] ` <008b01cf0a88$85df55f0$919e01d0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-01-06 11:23 ` Roland Stigge
2014-01-09 21:24 ` Wolfram Sang
2014-01-10 0:34 ` Jingoo Han
[not found] ` <001f01cf0d9b$aba03910$02e0ab30$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-01-13 12:29 ` Wolfram Sang
2014-01-14 0:09 ` Jingoo Han
2013-12-17 6:57 ` [PATCH 08/13] i2c: pxa: " Jingoo Han
2013-12-17 6:58 ` [PATCH 09/13] i2c: simtec: " Jingoo Han
2013-12-17 7:00 ` [PATCH 10/13] i2c: sirf: Use devm_clk_get() Jingoo Han
2013-12-17 7:00 ` [PATCH 11/13] i2c: versatile: Use devm_*() functions Jingoo Han
2013-12-17 7:01 ` [PATCH 12/13] i2c: viperboard: Use devm_kzalloc() functions Jingoo Han
[not found] ` <003001cefaf5$d6618590$832490b0$%han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-12-19 13:05 ` Lars Poeschel
2014-01-04 21:16 ` Wolfram Sang
2013-12-17 7:02 ` [PATCH 13/13] i2c: xiic: Use devm_*() functions Jingoo Han
2014-04-30 13:28 ` [PATCH 02/13] i2c: gpio: Use devm_gpio_request() Violeta Menendez Gonzalez
[not found] ` <5360FA98.3030503-4yDnlxn2s6sWdaTGBSpHTA@public.gmane.org>
2014-05-21 10:56 ` Wolfram Sang
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