drm/i915: Calculate correct stolen size for GEN7+
This bug existed in the old code, but was easier to fix here in the
rework. Unfortunately gen7 doesn't have a nice way to figure out the
size and we must use a lookup table.
As Jesse pointed out, there is some confusion in the docs about these
definitions. We're picking the one which seems more accurate, but we
really aren't certain.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index e74be0c..814ed3e 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -512,6 +512,15 @@
return snb_gmch_ctl << 25; /* 32 MB units */
}
+static inline unsigned int gen7_get_stolen_size(u16 snb_gmch_ctl)
+{
+ static const int stolen_decoder[] = {
+ 0, 0, 0, 0, 0, 32, 48, 64, 128, 256, 96, 160, 224, 352};
+ snb_gmch_ctl >>= IVB_GMCH_GMS_SHIFT;
+ snb_gmch_ctl &= IVB_GMCH_GMS_MASK;
+ return stolen_decoder[snb_gmch_ctl] << 20;
+}
+
int i915_gem_gtt_init(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -557,7 +566,10 @@
pci_read_config_word(dev->pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
dev_priv->mm.gtt->gtt_total_entries =
gen6_get_total_gtt_size(snb_gmch_ctl) / sizeof(gtt_pte_t);
- dev_priv->mm.gtt->stolen_size = gen6_get_stolen_size(snb_gmch_ctl);
+ if (INTEL_INFO(dev)->gen < 7)
+ dev_priv->mm.gtt->stolen_size = gen6_get_stolen_size(snb_gmch_ctl);
+ else
+ dev_priv->mm.gtt->stolen_size = gen7_get_stolen_size(snb_gmch_ctl);
dev_priv->mm.gtt->gtt_mappable_entries = pci_resource_len(dev->pdev, 2) >> PAGE_SHIFT;
/* 64/512MB is the current min/max we actually know of, but this is just a