Re: A spinlock_irqsave question

On 4/29/2013 10:30 AM, Ryan wrote:

> 
> 
> 
> spinlock_irqsave()  <== Disables the IRQ?
> 
>                             <== No IRQs (that means no KB
> interrupt,Interrupts from touch screen... etc..)
> 
> 
> 
> spinlock_irqrestore()
spin_lock_irqsave(lock,flags)/ affects the running
CPU, it does not disable any device IRQ. Device
interrupts may be taken by other CPUs. There is a whole
other set of calls that deal with individual IRQs.

> 
> 
> Is my understanding correct?
> So the "time spend between spinlock_irqsave and spinlock_restore
> should be very short?
> 
> For example there should not be something like this? Am i correct?
> 
> 
> spinlock_irqsave()
> 
> mdelay(1000);
> 
> 
> spinlock_irqrestore()

Yes, but much shorter then mdelay(1000)
> 
> 
> 
> 
> Also, what is meant by "spinlock_irqsave" disabled irq locally?

spin_lock_irqsave()disables interrupts on the CPU it's issued.




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