Attachment 93135 Details for Bug 74053 – One potential idea

[patch] One potential idea

0001-drm-i915-Prevent-MI_DISPLAY_FLIP-straddling-two-cach.patch (text/plain), 2.13 KB, created by Ville Syrjala on 2014-01-31 12:49:47 UTC

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Creator: Ville Syrjala

Created: 2014-01-31 12:49:47 UTC

Size: 2.13 KB

patch

obsolete

>From c52ed70cfd489da18d096a8a8d42acd4fb38897f Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
>Date: Fri, 31 Jan 2014 13:44:41 +0200
>Subject: [PATCH] drm/i915: Prevent MI_DISPLAY_FLIP straddling two cachelines
> on IVB
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>According to BSpec the entire MI_DISPLAY_FLIP packet must be contained
>in a single cacheline. Make sure that happens.
>
>Signed-off-by: Ville SyrjÃ¤lÃ¤ <ville.syrjala@linux.intel.com>
>---
> drivers/gpu/drm/i915/intel_display.c | 17 +++++++++++++++--
> 1 file changed, 15 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>index 4d4a0d9..5cf943a 100644
>--- a/drivers/gpu/drm/i915/intel_display.c
>+++ b/drivers/gpu/drm/i915/intel_display.c
>@@ -8565,7 +8565,7 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
> 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> 	struct intel_ring_buffer *ring;
> 	uint32_t plane_bit = 0;
>-	int len, ret;
>+	int len = 0, ret;
> 
> 	ring = obj->ring;
> 	if (IS_VALLEYVIEW(dev) || ring == NULL || ring->id != RCS)
>@@ -8591,10 +8591,19 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
> 		goto err_unpin;
> 	}
> 
>-	len = 4;
> 	if (ring->id == RCS)
> 		len += 6;
> 
>+	/*
>+	 * BSpec MI_DISPLAY_FLIP for IVB:
>+	 * "The full packet must be contained within the same cache line."
>+	 */
>+	if (ring->tail + len*4 + 4*4 <= ring->effective_size &&
>+	    (((ring->tail + len*4) & 63) > 64 - 4*4))
>+		len += (64 - ((ring->tail + len*4) & 63)) / 4;
>+
>+	len += 4;
>+
> 	ret = intel_ring_begin(ring, len);
> 	if (ret)
> 		goto err_unpin;
>@@ -8618,8 +8627,12 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
> 				MI_SRM_LRM_GLOBAL_GTT);
> 		intel_ring_emit(ring, DERRMR);
> 		intel_ring_emit(ring, ring->scratch.gtt_offset + 256);
>+		len -= 6;
> 	}
> 
>+	while (len-- > 4)
>+		intel_ring_emit(ring, MI_NOOP);
>+
> 	intel_ring_emit(ring, MI_DISPLAY_FLIP_I915 | plane_bit);
> 	intel_ring_emit(ring, (fb->pitches[0] | obj->tiling_mode));
> 	intel_ring_emit(ring, i915_gem_obj_ggtt_offset(obj) + intel_crtc->dspaddr_offset);
>-- 
>1.8.3.2
>

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Attachments on bug 74053: 92776 | 92780 | 93135 | 93513 | 93514 | 93534 | 95815

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