[Intel-gfx] [PATCH 5/5] drm/i915: Improve irq handling after gpu resets

[Ville Syrjälä]

On Thu, May 22, 2014 at 07:51:45PM +0300, Ville Syrjälä wrote:
> On Thu, May 22, 2014 at 05:56:35PM +0200, Daniel Vetter wrote:
> > Currently we do a full re-init of all interrupts after a gpu hang.
> > Which is pretty bad since we don't restore the interrupts we've
> > enabled at runtime correctly. Even with that addressed it's rather
> > horribly race.
> > 
> > But on g4x and later we only reset the gt and not the entire gpu.
> > Which means we only need to reset the GT interrupt bits. Which has the
> > nice benefit that vblank waits, pipe CRC interrupts and everything
> > else display related just keeps on working.
> > 
> > The downside is that gt interrupt handling (i.e. ring->get/put_irq) is
> > still racy. But as long as the gpu hang reliably wakes all waters and
> > we have a short time where the refcount drops to 0 we'll recover. So
> > not that bad really.
> 
> A quick test on IVB tells me that GTIMR and GEN6_PMIMR survive the full
> gt reset. But the ring IMRs do get clobbered. So could we just skip the
> entire irq reset here?

Same on ILK. GTIMR survives both render and media resets.

-- 
Ville Syrjälä
Intel OTC