Mesa (master): anv: Allow all clear colors for texturing on Gen11+

[GitLab Mirror]

Module: Mesa
Branch: master
Commit: 76d2772472037b2b9922f748170bebbce0b2a1de
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=76d2772472037b2b9922f748170bebbce0b2a1de

Author: Jason Ekstrand <jason at jlekstrand.net>
Date:   Tue Mar 31 17:46:37 2020 -0500

anv: Allow all clear colors for texturing on Gen11+

Starting with Gen11, we have two indirect clear colors: An unconverted
float/int version which is us used for rendering and a converted pixel
value version which is used for texturing.  Because the one used for
texturing is stored as a single pixel of that color, it works no matter
what format is being used.  Because it's a simple HW indirect and
doesn't involve copying surface states around, we can use it in the
sampler without having to worry about surface states having out-of-date
clear values.  The result is that we can now allow any clear color when
texturing.

This cuts the number of resolves in a RenderDoc trace of Dota2 by 95%
on Gen11+ (you read that right) and improves perf by 3.5%.  It improves
perf in a handful of other workloads by < 1%.

Reviewed-by: Rafael Antognolli <rafael.antognolli at intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4393>

---

 src/intel/vulkan/anv_image.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/intel/vulkan/anv_image.c b/src/intel/vulkan/anv_image.c
index 456fce1fc7f..19809884717 100644
--- a/src/intel/vulkan/anv_image.c
+++ b/src/intel/vulkan/anv_image.c
@@ -1604,12 +1604,20 @@ anv_layout_to_fast_clear_type(const struct gen_device_info * const devinfo,
          return ANV_FAST_CLEAR_ANY;
       } else if (image->planes[plane].aux_usage == ISL_AUX_USAGE_MCS ||
                  image->planes[plane].aux_usage == ISL_AUX_USAGE_CCS_E) {
-         /* If the image has MCS or CCS_E enabled all the time then we can use
-          * fast-clear as long as the clear color is the default value of zero
-          * since this is the default value we program into every surface
-          * state used for texturing.
-          */
-         return ANV_FAST_CLEAR_DEFAULT_VALUE;
+         if (devinfo->gen >= 11) {
+            /* On ICL and later, the sampler hardware uses a copy of the clear
+             * value that is encoded as a pixel value.  Therefore, we can use
+             * any clear color we like for sampling.
+             */
+            return ANV_FAST_CLEAR_ANY;
+         } else {
+            /* If the image has MCS or CCS_E enabled all the time then we can
+             * use fast-clear as long as the clear color is the default value
+             * of zero since this is the default value we program into every
+             * surface state used for texturing.
+             */
+            return ANV_FAST_CLEAR_DEFAULT_VALUE;
+         }
       } else {
          return ANV_FAST_CLEAR_NONE;
       }