From: Jean-Francois Moine <moinejf-GANU6spQydw@public.gmane.org>
To: Russell King <rmk+kernel-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>
Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>,
Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>,
"Mark A. Greer" <mgreer-luAo+O/VEmrlveNOaEYElw@public.gmane.org>,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Ben Dooks (embedded platforms)"
<ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>,
Sebastian Hesselbarth
<sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [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-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
On Thu, 16 May 2013 21:30:59 +0100
Russell King <rmk+kernel-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org> 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'hentañ | ** Breizh ha Linux atav! **
Jef | http://moinejf.free.fr/
WARNING: multiple messages have this Message-ID (diff)
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/
next prev parent reply other threads:[~2013-05-17 6:37 UTC|newest]
Thread overview: 42+ 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 20:29 ` 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
2013-05-16 20:30 ` Russell King
[not found] ` <E1Ud4pH-0004JQ-Jq-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-05-17 6:37 ` Jean-Francois Moine [this message]
2013-05-17 6:37 ` Jean-Francois Moine
2013-05-17 8:31 ` Russell King - ARM Linux
2013-05-17 8:31 ` Russell King - ARM Linux
2013-05-17 12:17 ` Wolfram Sang
2013-05-17 12:17 ` Wolfram Sang
2013-05-17 17:06 ` Mark A. Greer
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 20:32 ` Russell King
2013-05-16 20:33 ` [PATCH 3/9] I2C: mv64xxx: use devm_ioremap_resource() Russell King
2013-05-16 20:33 ` Russell King
[not found] ` <E1Ud4rN-0004Jc-CL-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-05-17 9:23 ` Jean-Francois Moine
2013-05-17 9:23 ` Jean-Francois Moine
2013-05-17 9:34 ` Russell King - ARM Linux
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 20:34 ` Russell King
2013-05-16 20:35 ` [PATCH 5/9] I2C: mv64xxx: use devm_kzalloc() Russell King
2013-05-16 20:35 ` Russell King
2013-05-16 20:36 ` [PATCH 6/9] I2C: mv64xxx: fix error handling for request_irq() Russell King
2013-05-16 20:36 ` Russell King
2013-05-16 20:37 ` [PATCH 7/9] I2C: mv64xxx: remove I2C_M_NOSTART code Russell King
2013-05-16 20:37 ` Russell King
[not found] ` <E1Ud4vH-0004Jz-F6-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-05-22 19:05 ` Mark Brown
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 20:38 ` Russell King
2013-05-16 20:39 ` [PATCH 9/9] I2C: mv64xxx: fix race between FSM/interrupt and process context Russell King
2013-05-16 20:39 ` Russell King
[not found] ` <E1Ud4xE-0004KB-2T-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-05-17 9:51 ` Wolfram Sang
2013-05-17 9:51 ` Wolfram Sang
2013-05-17 10:00 ` Russell King - ARM Linux
2013-05-17 10:00 ` Russell King - ARM Linux
[not found] ` <20130517100016.GB18614-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2013-05-17 12:15 ` Wolfram Sang
2013-05-17 12:15 ` Wolfram Sang
[not found] ` <20130516202921.GW18614-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2013-06-05 21:48 ` [PATCH 0/9] Fix Marvell mv63xxx I2C driver Wolfram Sang
2013-06-05 21:48 ` Wolfram Sang
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