[Intel-gfx] [PATCH 12/15] drm/i915: Interrupt routing for GuC submission

[Dave Gordon]

On 16/06/15 10:24, Chris Wilson wrote:
> On Mon, Jun 15, 2015 at 07:36:30PM +0100, Dave Gordon wrote:
>> +static void direct_interrupts_to_guc(struct drm_i915_private *dev_priv)
>> +{
>> +	struct intel_engine_cs *ring;
>> +	int i, irqs;
>> +
>> +	/* tell all command streamers to forward interrupts and vblank to GuC */
>> +	irqs = _MASKED_FIELD(GFX_FORWARD_VBLANK_MASK, GFX_FORWARD_VBLANK_ALWAYS);
>> +	irqs |= _MASKED_BIT_ENABLE(GFX_INTERRUPT_STEERING);
>> +	for_each_ring(ring, dev_priv, i)
>> +		I915_WRITE(RING_MODE_GEN7(ring), irqs);
>> +
>> +	/* tell DE to send (all) flip_done to GuC */
>> +	irqs = DERRMR_PIPEA_PRI_FLIP_DONE | DERRMR_PIPEA_SPR_FLIP_DONE |
>> +	       DERRMR_PIPEB_PRI_FLIP_DONE | DERRMR_PIPEB_SPR_FLIP_DONE |
>> +	       DERRMR_PIPEC_PRI_FLIP_DONE | DERRMR_PIPEC_SPR_FLIP_DONE;
>> +	/* Unmasked bits will cause GuC response message to be sent */
>> +	I915_WRITE(DE_GUCRMR, ~irqs);
> 
> That's scary since userspace depends on a few more DERRMR events
> (wait-for-scanline). Where will they end up?
> -Chris

This doesn't change any bits in DE_RRMR, or set the VBLANK or SCANLINE
bits in the DE_GUCRMR, so those events should be unaffected. The GuC
isn't interested in those, only in flip done.

.Dave.