Attachment 101855 Details for Bug 80151 – [PATCH] drm/i915: Add a guard page between stolen and GTT

[patch] [PATCH] drm/i915: Add a guard page between stolen and GTT

0001-drm-i915-Add-a-guard-page-between-stolen-and-GTT.patch (text/plain), 1.46 KB, created by Ville Syrjala on 2014-06-27 10:03:22 UTC

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Creator: Ville Syrjala

Created: 2014-06-27 10:03:22 UTC

Size: 1.46 KB

patch

obsolete

>From e9ef6c47147b3b0279d9056be719c3100c5a834f Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
>Date: Wed, 4 Jun 2014 17:55:19 +0300
>Subject: [PATCH] drm/i915: Add a guard page between stolen and GTT
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>I recall seeing a note somewhere that stated that we should put a guard
>page between stolen memory and the GTT. Something to do with preventing
>prefetches crossing into another memory type or something. Let's try it.
>
>Signed-off-by: Ville SyrjÃ¤lÃ¤ <ville.syrjala@linux.intel.com>
>---
> drivers/gpu/drm/i915/i915_gem_stolen.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
>index 2e418f8..aa45374 100644
>--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
>+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
>@@ -162,6 +162,12 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
> 			gtt_start &= PGTBL_ADDRESS_LO_MASK;
> 		gtt_end = gtt_start + gtt_total_entries(dev_priv->gtt) * 4;
> 
>+		/* add a guard page between GTT and rest of stolen */
>+		if (gtt_start >= stolen[0].start + PAGE_SIZE)
>+			gtt_start -= PAGE_SIZE;
>+		if (gtt_end + PAGE_SIZE <= stolen[0].end)
>+			gtt_end += PAGE_SIZE;
>+
> 		if (gtt_start >= stolen[0].start && gtt_start < stolen[0].end)
> 			stolen[0].end = gtt_start;
> 		if (gtt_end > stolen[1].start && gtt_end <= stolen[1].end)
>-- 
>1.8.5.5
>

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