Re: [PATCH] input: joystick: Adding Austria Microsystem AS5011joystick driver (third version)

From: Dmitry Torokhov
Date: Fri Jan 07 2011 - 14:50:15 EST


On Fri, Jan 07, 2011 at 08:42:37PM +0100, Fabien Marteau wrote:
> On 04/01/2011 12:01, Trilok Soni wrote:
> > Hi Fabien,
> >
> > On 1/4/2011 3:17 PM, Fabien Marteau wrote:
> >> +
> >> +static irqreturn_t as5011_int_interrupt(int irq, void *dev_id)
> >> +{
> >> + struct as5011_platform_data *plat_dat = dev_id;
> >> +
> >> + mutex_lock(&plat_dat->update_lock);
> >> + as5011_update_axes(plat_dat);
> >> + mutex_unlock(&plat_dat->update_lock);
> >
> > Please explain this lock. Sorry if I have missed out your explanation in the earlier threads.
>
> If a second interruption occurs the first update must be finished before update again.

The ISR handler will not be called simultaneously on several CPUs. What
else can it race with?

--
Dmitry
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