Re: [PATCH 1/2] PRUSS UIO driver support

[Thomas Gleixner]

On Fri, 18 Feb 2011, Arnd Bergmann wrote:

> On Friday 18 February 2011, Thomas Gleixner wrote:
> > On Fri, 18 Feb 2011, Arnd Bergmann wrote:
> > > On Friday 18 February 2011, Pratheesh Gangadhar wrote:
> > > > Signed-off-by: Pratheesh Gangadhar <pratheesh@xxxxxx>
> > > > +static irqreturn_t pruss_handler(int irq, struct uio_info *dev_info)
> > > > +{
> > > > +   return IRQ_HANDLED;
> > > > +}
> > > 
> > > An empty interrupt handler is rather pointless. I guess you really
> > > notify user space when the interrupt handler gets called, as this
> > > is the main point of a UIO driver as far as I understand it.
> > 
> > The UIO core code does this for you when the driver handler returns
> > IRQ_HANDLED
> 
> Ah, right.
> 
> > but the empty handler raises a different questions:
> > 
> > Is the interrupt edge triggerd or how do you avoid an irq storm here?
> > Usually UIO drivers are requested to mask the interrupt in the device
> > itself.
> 
> If it's edge triggered, it should not advertise IRQF_SHARED, right?

Nope. And the handler needs a fat comment why this works.

Thanks,

	tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/