[Mesa-dev] [PATCH] intel/gen6: Some framebuffers having separate depthstencil should be unsupported

[Chad Versace]

When the framebuffer has separate depth and stencil buffers, and HiZ is
not enabled on the depth buffer, mark the framebuffer as unsupported. This
happens when trying to create a framebuffer with Z16/S8 because we haven't
enabled HiZ on Z16 yet.

Fixes gles2conform test stencil8.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44948
Reported-by: Ian Romanick <ian.d.romanick at intel.com>
Note: This is a candiate for the 8.0 branch.
Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---
 src/mesa/drivers/dri/intel/intel_fbo.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/src/mesa/drivers/dri/intel/intel_fbo.c b/src/mesa/drivers/dri/intel/intel_fbo.c
index c37075c..45a6827 100644
--- a/src/mesa/drivers/dri/intel/intel_fbo.c
+++ b/src/mesa/drivers/dri/intel/intel_fbo.c
@@ -804,6 +804,15 @@ intel_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 	    fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 	 if (stencil_mt->format != MESA_FORMAT_S8)
 	    fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
+	 if (intel->gen < 7 && depth_mt->hiz_mt == NULL) {
+	    /* Before Gen7, separate depth and stencil buffers can be used
+	     * only if HiZ is enabled. From the Sandybridge PRM, Volume 2,
+	     * Part 1, Bit 3DSTATE_DEPTH_BUFFER.SeparateStencilBufferEnable:
+	     *     [DevSNB]: This field must be set to the same value (enabled
+	     *     or disabled) as Hierarchical Depth Buffer Enable.
+	     */
+	    fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED;
+	 }
       }
    }
 
-- 
1.7.7.4