Re: spin_lock_irqsave and ISP interrupts on OMAP 3530

[Adam Wozniak <awozniak@irobot.com>]

No one can confirm this?

On 02/03/2011 08:31 AM, Adam Wozniak wrote:
> I'm hoping I'm just not understanding something and this isn't as 
> broke as I fear it is.
>
> I'm using the ISP on an OMAP3530, linux 2.6.32.  I've got some kernel 
> code I want to lock in both the process context and the ISP interrupt 
> context, so I'm using a spinlock.  As I understand it, locking the 
> spinlock should disable all interrupts.  However, I'm still seeing the 
> ISP interrupt happen when I've got the spinlock locked in the process 
> context.
>
> i.e. somewhere I've got the code below, and my Warning is tripping.  
> Is this broken, or am I not understanding something?
>
> int am_i_locked = 0;
> spinlock_t my_spinlock = SPIN_LOCK_UNLOCKED;
>
> void foo(void) {
>     /* function could be called from process context, or could be 
> called from omap34xx_isp_isr (interrupt context) */
>     unsigned long flags;
>     spin_lock_irqsave(&my_spinlock, flags);
>     WARN_ON(am_i_locked);
>     am_i_locked++;
>
>     /* do some stuff */
>
>     am_i_locked--;
>     spin_unlock_irqrestore(&my_spinlock, flags);
> }
> -- 
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