intel/blorp: Only double the fast-clear rect alignment on HSW

This restriction was accidentally added to the BSpec/PRM as an
unrestricted restriction starting with the HSW docs and it was never
removed.  However, it only ever applied to HSW and actually potentially
causes problems on BDW and above where we have mipmapped fast-clears.

Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>

diff --git a/src/intel/blorp/blorp_clear.c b/src/intel/blorp/blorp_clear.c
index d7668eac3ca99888e9a422dbeea8e6e82635edd3..00447aa9690718c19d4c4abf62bd7531a0da23fd 100644 (file)
--- a/src/intel/blorp/blorp_clear.c
+++ b/src/intel/blorp/blorp_clear.c
@@ -259,16 +259,21 @@ get_fast_clear_rect(const struct isl_device *dev,
       x_scaledown = x_align / 2;
       y_scaledown = y_align / 2;
 
-      /* From BSpec: 3D-Media-GPGPU Engine > 3D Pipeline > Pixel > Pixel
-       * Backend > MCS Buffer for Render Target(s) [DevIVB+] > Table "Color
-       * Clear of Non-MultiSampled Render Target Restrictions":
-       *
-       *   Clear rectangle must be aligned to two times the number of
-       *   pixels in the table shown below due to 16x16 hashing across the
-       *   slice.
-       */
-      x_align *= 2;
-      y_align *= 2;
+      if (ISL_DEV_IS_HASWELL(dev)) {
+         /* From BSpec: 3D-Media-GPGPU Engine > 3D Pipeline > Pixel > Pixel
+          * Backend > MCS Buffer for Render Target(s) [DevIVB+] > Table "Color
+          * Clear of Non-MultiSampled Render Target Restrictions":
+          *
+          *   Clear rectangle must be aligned to two times the number of
+          *   pixels in the table shown below due to 16x16 hashing across the
+          *   slice.
+          *
+          * This restriction is only documented to exist on HSW GT3 but
+          * empirical evidence suggests that it's also needed GT2.
+          */
+         x_align *= 2;
+         y_align *= 2;
+      }
    } else {
       assert(aux_surf->usage == ISL_SURF_USAGE_MCS_BIT);