Attachment 25806 Details for Bug 21488 – Proposed fix for this hang

[patch] Proposed fix for this hang

0001-drm-i915-Don-t-allow-binding-objects-into-the-last.patch (text/plain), 1.60 KB, created by Eric Anholt on 2009-05-12 15:31:31 UTC

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Creator: Eric Anholt

Created: 2009-05-12 15:31:31 UTC

Size: 1.60 KB

patch

obsolete

>From 1e97dadfb1711087c7a037a0e1e543ed64be14f8 Mon Sep 17 00:00:00 2001
>From: Eric Anholt <eric@anholt.net>
>Date: Tue, 12 May 2009 15:27:36 -0700
>Subject: [PATCH] drm/i915: Don't allow binding objects into the last page of the aperture.
>
>This should avoid a class of bugs where the hardware prefetches past the
>end of the object, and walks into unallocated memory when the object is
>bound to the last page of the aperture.
>
>fd.o bug #21488
>---
> drivers/gpu/drm/i915/i915_dma.c |   12 ++++++++++--
> 1 files changed, 10 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
>index 051134c..3133f99 100644
>--- a/drivers/gpu/drm/i915/i915_dma.c
>+++ b/drivers/gpu/drm/i915/i915_dma.c
>@@ -1011,8 +1011,16 @@ static int i915_load_modeset_init(struct drm_device *dev)
> 	/* Basic memrange allocator for stolen space (aka vram) */
> 	drm_mm_init(&dev_priv->vram, 0, prealloc_size);
> 
>-	/* Let GEM Manage from end of prealloc space to end of aperture */
>-	i915_gem_do_init(dev, prealloc_size, agp_size);
>+	/* Let GEM Manage from end of prealloc space to end of aperture.
>+	 *
>+	 * However, leave one page at the end still bound to the scratch page.
>+	 * There are a number of places where the hardware apparently
>+	 * prefetches past the end of the object, and we've seen multiple
>+	 * hangs with the GPU head pointer stuck in a batchbuffer bound
>+	 * at the last page of the aperture.  One page should be enough to
>+	 * keep any prefetching inside of the aperture.
>+	 */
>+	i915_gem_do_init(dev, prealloc_size, agp_size - 4096);
> 
> 	ret = i915_gem_init_ringbuffer(dev);
> 	if (ret)
>-- 
>1.6.2.4
>

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