On Fri, Nov 1, 2013 at 5:04 PM, Ben Widawsky
wrote:
> When not blitting to scanout, we can save some power by not tracking
> blits, and more importantly, unnecessarily invalidating lines which we
> don't care a bout.
>
> These instructions are explicitly spelled out in the spec, but it is how
> I expect it to work. Unfortunately, I do not have power data for this.
>
> v2: Don't advance the ring twice (Stéphane)
> Rename extra_dwords to dwrods (Stéphane)
>
> Cc: Stéphane Marchesin
> Signed-off-by: Ben Widawsky
For both:
Tested-by: Stéphane Marchesin
Reviewed-by: Stéphane Marchesin
Stéphane
> ---
> drivers/gpu/drm/i915/intel_ringbuffer.c | 20 +---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c
> b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index ddd7681..8c6e9b2 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -296,7 +296,8 @@ static int gen6_ring_fbc_flush(struct intel_ring_buffer
> *ring)
> _MASKED_BIT_ENABLE(GEN6_BLITTER_FBC_NOTIFY));
> intel_ring_advance(ring);
>
> - ring->fbc_dirty = false;
> + /* We'll mark the fbc clean only after the operation has completed so
> we
> +* can track when to disable the bit above */
> return 0;
> }
>
> @@ -642,11 +643,13 @@ gen6_add_request(struct intel_ring_buffer *ring)
> struct drm_device *dev = ring->dev;
> struct drm_i915_private *dev_priv = dev->dev_private;
> struct intel_ring_buffer *useless;
> - int i, ret;
> + int i, ret, dwords = 4;
>
> + if (ring->fbc_dirty && ring->id == BCS)
> + dwords += 4;
> ret = intel_ring_begin(ring, ((I915_NUM_RINGS-1) *
> MBOX_UPDATE_DWORDS) +
> - 4);
> + dwords);
> if (ret)
> return ret;
> #undef MBOX_UPDATE_DWORDS
> @@ -661,6 +664,17 @@ gen6_add_request(struct intel_ring_buffer *ring)
> intel_ring_emit(ring, I915_GEM_HWS_INDEX <<
> MI_STORE_DWORD_INDEX_SHIFT);
> intel_ring_emit(ring, ring->outstanding_lazy_seqno);
> intel_ring_emit(ring, MI_USER_INTERRUPT);
> +
> + if (ring->fbc_dirty && ring->id == BCS) {
> + intel_ring_emit(ring, MI_NOOP);
> + intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
> + intel_ring_emit(ring, GEN6_BLITTER_ECOSKPD);
> + intel_ring_emit(ring,
> + _MASKED_BIT_DISABLE(GEN6_BLITTER_FBC_NOTIFY));
> +
> + ring->fbc_dirty = false;
> + }
> +
> __intel_ring_advance(ring);
>
> return 0;
> --
> 1.8.4.2
>
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