Commit c890e2d5 authored Mar 18, 2016 by Chris Wilson Committed by Joonas Lahtinen Mar 18, 2016

drm/i915: Codify our assumption that the Global GTT is <= 4GiB

Throughout the code base, we use u32 for offsets into the global GTT. If
we ever see any hardware with a larger GGTT, then we run the real risk
of silent corruption. So test for our assumption up front so that we
have a nice reminder should the time come when it fails.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
[Rebased and changed 1ull -> 1ULL, cut 80 char line]
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1458290579-27783-1-git-send-email-joonas.lahtinen@linux.intel.com

parent d507d735

drivers/gpu/drm/i915/i915_gem_gtt.c

+8 −0

Original line number	Original line	Diff line number	Diff line
	@@ -3191,6 +3191,14 @@ int i915_gem_gtt_init(struct drm_device *dev)
	if (ret)		if (ret)
	return ret;		return ret;

			if ((ggtt->base.total - 1) >> 32) {
			DRM_ERROR("We never expected a Global GTT with more than 32bits"
			"of address space! Found %lldM!\n",
			ggtt->base.total >> 20);
			ggtt->base.total = 1ULL << 32;
			ggtt->mappable_end = min(ggtt->mappable_end, ggtt->base.total);
			}

	/*		/*
	* Initialise stolen early so that we may reserve preallocated		* Initialise stolen early so that we may reserve preallocated
	* objects for the BIOS to KMS transition.		* objects for the BIOS to KMS transition.