On 08/04/2014 at 15:34:04 +0800, Shawn Guo wrote : > On Fri, Apr 04, 2014 at 06:44:47PM +0200, Alexandre Belloni wrote: > > 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. > > Right, per kerneldoc of struct pwm_chip, we should set can_sleep. > > /** > * struct pwm_chip - abstract a PWM controller > * ... > * @can_sleep: must be true if the .config(), .enable() or .disable() > * operations may sleep > */ > > But how does setting the flag make a difference there? I see pwm core > does nothing about the flag, or am I missing something? > The driver using the PWM should test the flag, have a look at: http://lxr.free-electrons.com/source/drivers/leds/leds-pwm.c#L183 -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
