Attachment 128440 Details for Bug 94605 – Possible fix, patch 2.

[patch] Possible fix, patch 2.

0002-drm-i915-fully-apply-WaSkipStolenMemoryFirstPage.patch (text/plain), 3.00 KB, created by Paulo Zanoni on 2016-12-12 20:46:13 UTC

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Creator: Paulo Zanoni

Created: 2016-12-12 20:46:13 UTC

Size: 3.00 KB

patch

obsolete

>From 8ea2b2aa66703cafff657ca49a22e123822ba21f Mon Sep 17 00:00:00 2001
>From: Paulo Zanoni <paulo.r.zanoni@intel.com>
>Date: Mon, 12 Dec 2016 18:22:47 -0200
>Subject: [PATCH 2/2] drm/i915: fully apply WaSkipStolenMemoryFirstPage
>
>Reserve the first page of stolen memory right after initializing the
>mm allocator. This means that we won't inherit the FB in case
>the BIOS decides to put it at the start of stolen.
>
>TODO: the goal is to ask everybody with screen flickering problems to
>test this patch. Hopefully we'll be able to add a bunch of Bugzilla
>tags here before merging it.
>
>Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
>---
> drivers/gpu/drm/i915/i915_drv.h        |  3 +++
> drivers/gpu/drm/i915/i915_gem_stolen.c | 26 +++++++++-----------------
> 2 files changed, 12 insertions(+), 17 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>index 727d2aa..994eb24 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -1531,6 +1531,9 @@ struct i915_gem_mm {
> 	/** LRU list of objects with fence regs on them. */
> 	struct list_head fence_list;
> 
>+	/** First page of stolen, for platforms where it's reserved. */
>+	struct drm_mm_node first_page;
>+
> 	/**
> 	 * Are we in a non-interruptible section of code like
> 	 * modesetting?
>diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
>index b1c8897..30d645d 100644
>--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
>+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
>@@ -54,12 +54,6 @@ int i915_gem_stolen_insert_node_in_range(struct drm_i915_private *dev_priv,
> 	if (!drm_mm_initialized(&dev_priv->mm.stolen))
> 		return -ENODEV;
> 
>-	/* See the comment at the drm_mm_init() call for more about this check.
>-	 * WaSkipStolenMemoryFirstPage:bdw+ (incomplete)
>-	 */
>-	if (start < 4096 && INTEL_GEN(dev_priv) >= 8)
>-		start = 4096;
>-
> 	mutex_lock(&dev_priv->mm.stolen_lock);
> 	ret = drm_mm_insert_node_in_range(&dev_priv->mm.stolen, node, size,
> 					  alignment, start, end,
>@@ -491,19 +485,17 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
> 
> 	ggtt->stolen_usable_size = ggtt->stolen_size - reserved_total;
> 
>-	/*
>-	 * Basic memrange allocator for stolen space.
>-	 *
>-	 * TODO: Notice that some platforms require us to not use the first page
>-	 * of the stolen memory but their BIOSes may still put the framebuffer
>-	 * on the first page. So we don't reserve this page for now because of
>-	 * that. Our current solution is to just prevent new nodes from being
>-	 * inserted on the first page - see the check we have at
>-	 * i915_gem_stolen_insert_node_in_range(). We may want to fix the fbcon
>-	 * problem later.
>-	 */
>+	/* Basic memrange allocator for stolen space. */
> 	drm_mm_init(&dev_priv->mm.stolen, 0, ggtt->stolen_usable_size);
> 
>+	/* WaSkipStolenMemoryFirstPage:bdw+ */
>+	if (INTEL_GEN(dev_priv) >= 8) {
>+		dev_priv->mm.first_page.start = 0;
>+		dev_priv->mm.first_page.size = 4096;
>+		drm_mm_reserve_node(&dev_priv->mm.stolen,
>+				    &dev_priv->mm.first_page);
>+	}
>+
> 	return 0;
> }
> 
>-- 
>2.7.4
>

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Attachments on bug 94605: 122395 | 123549 | 123550 | 126597 | 126598 | 126599 | 128001 | 128027 | 128357 | 128373 | 128413 | 128439 | 128440

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