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Commit 1ca36d4c authored by Paulo Zanoni's avatar Paulo Zanoni Committed by Daniel Vetter
Browse files

drm/i915: don't use the first stolen page on Broadwell 



The spec says we just can't use it.

v2:
  - Add WA name (Ville).
  - Add a big comment explaining that we still didn't fix the problem
    where we inherit a framebuffer on the first page (Chris, Ville).

Signed-off-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Acked-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent b26d3ea3

drivers/gpu/drm/i915/i915_gem_stolen.c

+16 −1
Original line number Diff line number Diff line
@@ -51,6 +51,11 @@ 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,chv (incomplete) */

	if (INTEL_INFO(dev_priv)->gen == 8 && start < 4096)

		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,
@@ -393,7 +398,17 @@ int i915_gem_init_stolen(struct drm_device *dev) 
	dev_priv->gtt.stolen_usable_size = dev_priv->gtt.stolen_size -

					   reserved_total;



	/* Basic memrange allocator for stolen space */

	/*

	 * 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.

	 */

	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_usable_size);



	return 0;