[Intel-gfx] [PATCH] [drm/i915] Always read pipestat in irq_handler

[Jesse Barnes]

On Friday, November 28, 2008 10:24 am Keith Packard wrote:
> On Fri, 2008-11-28 at 17:13 +0800, Li Peng wrote:
> >  	iir = I915_READ(IIR);
> >
> > +	if (iir == 0)
> > +		return IRQ_NONE;
> > +
>
> We can't do that -- iir may be zero while there are still pipe
> interrupts pending, due to the ordering between pipe stat writes and iir
> writes. However, it looks like we need to ensure that the pipe stat
> values are set before enabling interrupts.

I think this particular problem should go away once your change to init the 
vblank structures at load time makes it upstream, since it'll be safe to 
handle a vblank event at that point.

-- 
Jesse Barnes, Intel Open Source Technology Center