Mesa (master): gen7 fbo: make unmatched depth/ stencil configs return unsupported

[Jordan Justen]

Module: Mesa
Branch: master
Commit: f3c886be1f53a29377af4649876f0d90418764a9
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f3c886be1f53a29377af4649876f0d90418764a9

Author: Jordan Justen <jordan.l.justen at intel.com>
Date:   Fri Jul 19 15:44:56 2013 -0700

gen7 fbo: make unmatched depth/stencil configs return unsupported

For gen >= 7, we will use the lod/minimum-array-element fields to
support layered rendering. This means that we must restrict
the depth & stencil attachments to match in various more retrictive
ways. (Now the width, height, depth, LOD and layer must match)

The reason width, height, and depth must match is that the hardware
has a single set of width, height, and depth settings (in
3DSTATE_DEPTH_BUFFER) that affect both the depth and stencil buffers.
Since these controls determine the miptree layout, they need to be
set correctly in order for lod and minimum-array-element to work
properly.  So the only way rendering can work is if the width,
height, and depth match.

In the future, if this restriction proves to be a problem (say
because some crucial client application relies on rendering to
different levels/layers of stencil and depth buffers), then we can
always work around the restriction by copying depth and/or stencil
data to a temporary buffer prior to rendering (much in the same way
that brw_workaround_depthstencil_alignment() does today for
gen < 7), but hopefully that won't be necessary.

Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
Reviewed-by: Paul Berry <stereotype441 at gmail.com>

---

 src/mesa/drivers/dri/i965/intel_fbo.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_fbo.c b/src/mesa/drivers/dri/i965/intel_fbo.c
index 4540904..5d5d8b5 100644
--- a/src/mesa/drivers/dri/i965/intel_fbo.c
+++ b/src/mesa/drivers/dri/i965/intel_fbo.c
@@ -583,6 +583,22 @@ intel_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
    }
 
    if (depth_mt && stencil_mt) {
+      if (brw->gen >= 7) {
+         /* For gen >= 7, we are using the lod/minimum-array-element fields
+          * and supportting layered rendering. This means that we must restrict
+          * the depth & stencil attachments to match in various more retrictive
+          * ways. (width, height, depth, LOD and layer)
+          */
+	 if (depth_mt->physical_width0 != stencil_mt->physical_width0 ||
+             depth_mt->physical_height0 != stencil_mt->physical_height0 ||
+             depth_mt->physical_depth0 != stencil_mt->physical_depth0 ||
+             depthRb->mt_level != stencilRb->mt_level ||
+	     depthRb->mt_layer != stencilRb->mt_layer) {
+	    fbo_incomplete(fb,
+                           "FBO incomplete: depth and stencil must match in"
+                           "width, height, depth, LOD and layer\n");
+	 }
+      }
       if (depth_mt == stencil_mt) {
 	 /* For true packed depth/stencil (not faked on prefers-separate-stencil
 	  * hardware) we need to be sure they're the same level/layer, since