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From: moinejf@free.fr (Jean-Francois Moine)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/9] I2C: mv64xxx: work around signals causing I2C transactions to be aborted
Date: Fri, 17 May 2013 08:37:43 +0200	[thread overview]
Message-ID: <20130517083743.31af4eb0@armhf> (raw)
In-Reply-To: <E1Ud4pH-0004JQ-Jq@rmk-PC.arm.linux.org.uk>

On Thu, 16 May 2013 21:30:59 +0100
Russell King <rmk+kernel@arm.linux.org.uk> wrote:

> Do not use interruptible waits in an I2C driver; if a process uses
> signals (eg, Xorg uses SIGALRM and SIGPIPE) then these signals can
> cause the I2C driver to abort a transaction in progress by another
> driver, which can cause that driver to fail.  I2C drivers are not
> expected to abort transactions on signals.

Hi Russell,

I had the same problem with my dove drm driver, but I don't fully agree
with your solution.

Using wait_event_timeout() stops the system, and reading the EDID from
an external screen may take some time.

Instead, as the problem occurs with the X server on HDMI exchanges,
I acted on the tda998x driver, simply masking the SIGALRM and SIGPIPE
signals on each drm driver request.

This mechanism works fine for me. Patch follows.

-- 
Ken ar c'henta?	|	      ** Breizh ha Linux atav! **
Jef		|		http://moinejf.free.fr/

  reply	other threads:[~2013-05-17  6:37 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-16 20:29 [PATCH 0/9] Fix Marvell mv63xxx I2C driver Russell King - ARM Linux
2013-05-16 20:30 ` [PATCH 1/9] I2C: mv64xxx: work around signals causing I2C transactions to be aborted Russell King
2013-05-17  6:37   ` Jean-Francois Moine [this message]
2013-05-17  8:31     ` Russell King - ARM Linux
2013-05-17 12:17   ` Wolfram Sang
2013-05-17 17:06   ` Mark A. Greer
2013-05-16 20:32 ` [PATCH 2/9] I2C: mv64xxx: use return value from mv64xxx_i2c_map_regs() Russell King
2013-05-16 20:33 ` [PATCH 3/9] I2C: mv64xxx: use devm_ioremap_resource() Russell King
2013-05-17  9:23   ` Jean-Francois Moine
2013-05-17  9:34     ` Russell King - ARM Linux
2013-05-16 20:34 ` [PATCH 4/9] I2C: mv64xxx: use devm_clk_get() to avoid missing clk_put() Russell King
2013-05-16 20:35 ` [PATCH 5/9] I2C: mv64xxx: use devm_kzalloc() Russell King
2013-05-16 20:36 ` [PATCH 6/9] I2C: mv64xxx: fix error handling for request_irq() Russell King
2013-05-16 20:37 ` [PATCH 7/9] I2C: mv64xxx: remove I2C_M_NOSTART code Russell King
2013-05-22 19:05   ` Mark Brown
2013-05-16 20:38 ` [PATCH 8/9] I2C: mv64xxx: move mv64xxx_i2c_prepare_for_io() Russell King
2013-05-16 20:39 ` [PATCH 9/9] I2C: mv64xxx: fix race between FSM/interrupt and process context Russell King
2013-05-17  9:51   ` Wolfram Sang
2013-05-17 10:00     ` Russell King - ARM Linux
2013-05-17 12:15       ` Wolfram Sang
2013-06-05 21:48 ` [PATCH 0/9] Fix Marvell mv63xxx I2C driver Wolfram Sang

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