drm/i915: avoid the last 8mb of stolen on BDW/SKL
The FBC hardware for these platforms doesn't have access to the
bios_reserved range, so it always assumes the maximum (8mb) is used.
So avoid this range while allocating.
This solves a bunch of FIFO underruns that happen if you end up
putting the CFB in that memory range. On my machine, with 32mb of
stolen, I need a 2560x1440 mode for that.
Testcase: igt/kms_frontbuffer_tracking/fbc-* (given the right setup)
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index db38091..6f3c2ea 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -551,6 +551,16 @@
{
int compression_threshold = 1;
int ret;
+ u64 end;
+
+ /* The FBC hardware for BDW/SKL doesn't have access to the stolen
+ * reserved range size, so it always assumes the maximum (8mb) is used.
+ * If we enable FBC using a CFB on that memory range we'll get FIFO
+ * underruns, even if that range is not reserved by the BIOS. */
+ if (IS_BROADWELL(dev_priv) || IS_SKYLAKE(dev_priv))
+ end = dev_priv->gtt.stolen_size - 8 * 1024 * 1024;
+ else
+ end = dev_priv->gtt.stolen_usable_size;
/* HACK: This code depends on what we will do in *_enable_fbc. If that
* code changes, this code needs to change as well.
@@ -560,7 +570,8 @@
*/
/* Try to over-allocate to reduce reallocations and fragmentation. */
- ret = i915_gem_stolen_insert_node(dev_priv, node, size <<= 1, 4096);
+ ret = i915_gem_stolen_insert_node_in_range(dev_priv, node, size <<= 1,
+ 4096, 0, end);
if (ret == 0)
return compression_threshold;
@@ -570,7 +581,8 @@
(fb_cpp == 2 && compression_threshold == 2))
return 0;
- ret = i915_gem_stolen_insert_node(dev_priv, node, size >>= 1, 4096);
+ ret = i915_gem_stolen_insert_node_in_range(dev_priv, node, size >>= 1,
+ 4096, 0, end);
if (ret && INTEL_INFO(dev_priv)->gen <= 4) {
return 0;
} else if (ret) {