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authorJason Ekstrand <jason.ekstrand@intel.com>2017-07-22 16:50:22 -0700
committerJason Ekstrand <jason.ekstrand@intel.com>2017-07-22 20:12:07 -0700
commitf793c57cc583371a4f9e0d04220eb60e91c0319a (patch)
treeb23fb494f94ae1778ca23a24ddab650d78151828 /src/intel
parent4aee05b6c64a18c4213dcdd3315eb2b8dd43c587 (diff)
intel/isl: Tighten up restrictions for CCS on gen7
It may technically be possible to enable some sort of fast-clear support for at least the base slice of a 2D array texture on gen7. However, it's not documented to work, we've never tried to do it in GL, and we have no idea what the hardware does if you turn on CCS_D with arrayed rendering. Let's just play it safe and disallow it for now. If someone really cares that much about gen7 performance, they can come along and try to get it working later.
Diffstat (limited to 'src/intel')
-rw-r--r--src/intel/isl/isl.c30
1 files changed, 23 insertions, 7 deletions
diff --git a/src/intel/isl/isl.c b/src/intel/isl/isl.c
index 8cfec47733c..e7e5530e5bf 100644
--- a/src/intel/isl/isl.c
+++ b/src/intel/isl/isl.c
@@ -1740,9 +1740,30 @@ isl_surf_get_ccs_surf(const struct isl_device *dev,
if (surf->usage & ISL_SURF_USAGE_DISABLE_AUX_BIT)
return false;
+ /* The PRM doesn't say this explicitly, but fast-clears don't appear to
+ * work for 3D textures until gen9 where the layout of 3D textures changes
+ * to match 2D array textures.
+ */
if (ISL_DEV_GEN(dev) <= 8 && surf->dim != ISL_SURF_DIM_2D)
return false;
+ /* From the HSW PRM Volume 7: 3D-Media-GPGPU, page 652 (Color Clear of
+ * Non-MultiSampler Render Target Restrictions):
+ *
+ * "Support is for non-mip-mapped and non-array surface types only."
+ *
+ * This restriction is lifted on gen8+. Technically, it may be possible to
+ * create a CCS for an arrayed or mipmapped image and only enable CCS_D
+ * when rendering to the base slice. However, there is no documentation
+ * tell us what the hardware would do in that case or what it does if you
+ * walk off the bases slice. (Does it ignore CCS or does it start
+ * scribbling over random memory?) We play it safe and just follow the
+ * docs and don't allow CCS_D for arrayed or mip-mapped surfaces.
+ */
+ if (ISL_DEV_GEN(dev) <= 7 &&
+ (surf->levels > 1 || surf->logical_level0_px.array_len > 1))
+ return false;
+
if (isl_format_is_compressed(surf->format))
return false;
@@ -1780,19 +1801,14 @@ isl_surf_get_ccs_surf(const struct isl_device *dev,
return false;
}
- /* Multi-LOD and multi-layer CCS isn't supported on gen7. */
- const uint8_t levels = ISL_DEV_GEN(dev) <= 7 ? 1 : surf->levels;
- const uint32_t array_len = ISL_DEV_GEN(dev) <= 7 ?
- 1 : surf->logical_level0_px.array_len;
-
return isl_surf_init(dev, ccs_surf,
.dim = surf->dim,
.format = ccs_format,
.width = surf->logical_level0_px.width,
.height = surf->logical_level0_px.height,
.depth = surf->logical_level0_px.depth,
- .levels = levels,
- .array_len = array_len,
+ .levels = surf->levels,
+ .array_len = surf->logical_level0_px.array_len,
.samples = 1,
.row_pitch = row_pitch,
.usage = ISL_SURF_USAGE_CCS_BIT,