From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Shawn Guo <shawn.guo@freescale.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>,
Fabio Estevam <fabio.estevam@freescale.com>,
Thierry Reding <thierry.reding@gmail.com>,
Bryan Wu <cooloney@gmail.com>, Richard Purdie <rpurdie@rpsys.net>,
Sascha Hauer <kernel@pengutronix.de>,
linux-arm-kernel@lists.infradead.org, linux-pwm@vger.kernel.org,
linux-leds@vger.kernel.org
Subject: Re: MX28: leds/pwm: Using pwm driven led as heartbeat leads to kernel warning
Date: Fri, 4 Apr 2014 18:44:47 +0200 [thread overview]
Message-ID: <20140404164446.GI4883@piout.net> (raw)
In-Reply-To: <20140404142656.GA16383@dragon>
On 04/04/2014 at 22:26:58 +0800, Shawn Guo wrote :
> On Fri, Apr 04, 2014 at 03:54:52PM +0200, Stefan Wahren wrote:
> > the problem is still reproducable in Mainline 3.14.0 and gives the same
> > warning message.
> > Also i add linux-leds in CC.
> >
> > Are there any advices to narrow down the problem?
> >
> > Is this problem specific to i.MX28 PWM (i don't have other kind of
> > hardware)?
>
> I don't think it's specific to i.MX28 PWM. Since the .config hook of
> pwm_ops will be called from interrupt context in this case, any pwm
> drivers that do sleeping calls in the hook will have this problem, e.g.
> the clk APIs that hold mutex like clk_prepare() and clk_get_rate() etc.
>
Yeah, I'm wondering whether we should set pwm->chip->can_sleep then.
Thierry, do you have an opinion ?
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: alexandre.belloni@free-electrons.com (Alexandre Belloni)
To: linux-arm-kernel@lists.infradead.org
Subject: MX28: leds/pwm: Using pwm driven led as heartbeat leads to kernel warning
Date: Fri, 4 Apr 2014 18:44:47 +0200 [thread overview]
Message-ID: <20140404164446.GI4883@piout.net> (raw)
In-Reply-To: <20140404142656.GA16383@dragon>
On 04/04/2014 at 22:26:58 +0800, Shawn Guo wrote :
> On Fri, Apr 04, 2014 at 03:54:52PM +0200, Stefan Wahren wrote:
> > the problem is still reproducable in Mainline 3.14.0 and gives the same
> > warning message.
> > Also i add linux-leds in CC.
> >
> > Are there any advices to narrow down the problem?
> >
> > Is this problem specific to i.MX28 PWM (i don't have other kind of
> > hardware)?
>
> I don't think it's specific to i.MX28 PWM. Since the .config hook of
> pwm_ops will be called from interrupt context in this case, any pwm
> drivers that do sleeping calls in the hook will have this problem, e.g.
> the clk APIs that hold mutex like clk_prepare() and clk_get_rate() etc.
>
Yeah, I'm wondering whether we should set pwm->chip->can_sleep then.
Thierry, do you have an opinion ?
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2014-04-04 16:44 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-27 17:14 MX28: leds/pwm: Using pwm driven led as heartbeat leads to kernel warning Stefan Wahren
2014-03-27 17:14 ` Stefan Wahren
2014-04-04 13:54 ` Stefan Wahren
2014-04-04 13:54 ` Stefan Wahren
2014-04-04 14:26 ` Shawn Guo
2014-04-04 14:26 ` Shawn Guo
2014-04-04 15:25 ` Stefan Wahren
2014-04-04 15:25 ` Stefan Wahren
2014-04-04 16:44 ` Alexandre Belloni [this message]
2014-04-04 16:44 ` Alexandre Belloni
2014-04-08 7:34 ` Shawn Guo
2014-04-08 7:34 ` Shawn Guo
2014-04-08 7:59 ` Alexandre Belloni
2014-04-08 7:59 ` Alexandre Belloni
2014-04-08 8:18 ` Shawn Guo
2014-04-08 8:18 ` Shawn Guo
2014-04-08 8:41 ` Alexandre Belloni
2014-04-08 8:41 ` Alexandre Belloni
2014-04-08 8:49 ` Shawn Guo
2014-04-08 8:49 ` Shawn Guo
2014-04-08 9:04 ` Alexandre Belloni
2014-04-08 9:04 ` Alexandre Belloni
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