intel: Convert to using private depth/stencil buffers (v2)

This means that GLX buffer sharing of these no longer works.  On the
other hand, just *look* at this code reduction.

v2:
  - [chad] Fix intelCreateBuffer for gen < 6. When the branch for
    !screen->hw_has_separate_stencil was taken,
    intel_create_private_renderbuffer was incorrectly not used.

  - [chad] Remove all code in intel_process_dri2_buffer for processing
    depth, stencil, and hiz buffers. That code is now dead.

CC: Eric Anholt <eric@anholt.net>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

1 files changed, 34 insertions, 582 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c
index c2f7d2956ef..60e93f0dc3e 100644
--- a/src/mesa/drivers/dri/intel/intel_context.c
+++ b/src/mesa/drivers/dri/intel/intel_context.c
@@ -239,37 +239,17 @@ intel_bits_per_pixel(const struct intel_renderbuffer *rb)
 }
 
 static void
-intel_query_dri2_buffers_no_separate_stencil(struct intel_context *intel,
-					     __DRIdrawable *drawable,
-					     __DRIbuffer **buffers,
-					     int *count);
+intel_query_dri2_buffers(struct intel_context *intel,
+			 __DRIdrawable *drawable,
+			 __DRIbuffer **buffers,
+			 int *count);
 
 static void
-intel_process_dri2_buffer_no_separate_stencil(struct intel_context *intel,
-					      __DRIdrawable *drawable,
-					      __DRIbuffer *buffer,
-					      struct intel_renderbuffer *rb,
-					      const char *buffer_name);
-
-static void
-intel_query_dri2_buffers_with_separate_stencil(struct intel_context *intel,
-					       __DRIdrawable *drawable,
-					       __DRIbuffer **buffers,
-					       unsigned **attachments,
-					       int *count);
-
-static void
-intel_process_dri2_buffer_with_separate_stencil(struct intel_context *intel,
-						__DRIdrawable *drawable,
-						__DRIbuffer *buffer,
-						struct intel_renderbuffer *rb,
-						const char *buffer_name);
-static void
-intel_verify_dri2_has_hiz(struct intel_context *intel,
+intel_process_dri2_buffer(struct intel_context *intel,
 			  __DRIdrawable *drawable,
-			  __DRIbuffer **buffers,
-			  unsigned **attachments,
-			  int *count);
+			  __DRIbuffer *buffer,
+			  struct intel_renderbuffer *rb,
+			  const char *buffer_name);
 
 void
 intel_update_renderbuffers(__DRIcontext *context, __DRIdrawable *drawable)
@@ -278,19 +258,9 @@ intel_update_renderbuffers(__DRIcontext *context, __DRIdrawable *drawable)
    struct intel_renderbuffer *rb;
    struct intel_context *intel = context->driverPrivate;
    __DRIbuffer *buffers = NULL;
-   unsigned *attachments = NULL;
    int i, count;
    const char *region_name;
 
-   bool try_separate_stencil =
-      intel->has_separate_stencil &&
-      intel->intelScreen->dri2_has_hiz != INTEL_DRI2_HAS_HIZ_FALSE &&
-      intel->intelScreen->driScrnPriv->dri2.loader != NULL &&
-      intel->intelScreen->driScrnPriv->dri2.loader->base.version > 2 &&
-      intel->intelScreen->driScrnPriv->dri2.loader->getBuffersWithFormat != NULL;
-
-   assert(!intel->must_use_separate_stencil || try_separate_stencil);
-
    /* If we're rendering to the fake front buffer, make sure all the
     * pending drawing has landed on the real front buffer.  Otherwise
     * when we eventually get to DRI2GetBuffersWithFormat the stale
@@ -310,13 +280,7 @@ intel_update_renderbuffers(__DRIcontext *context, __DRIdrawable *drawable)
    if (unlikely(INTEL_DEBUG & DEBUG_DRI))
       fprintf(stderr, "enter %s, drawable %p\n", __func__, drawable);
 
-   if (try_separate_stencil) {
-      intel_query_dri2_buffers_with_separate_stencil(intel, drawable, &buffers,
-						     &attachments, &count);
-   } else {
-      intel_query_dri2_buffers_no_separate_stencil(intel, drawable, &buffers,
-						   &count);
-   }
+   intel_query_dri2_buffers(intel, drawable, &buffers, &count);
 
    if (buffers == NULL)
       return;
@@ -339,26 +303,9 @@ intel_update_renderbuffers(__DRIcontext *context, __DRIdrawable *drawable)
 	   break;
 
        case __DRI_BUFFER_DEPTH:
-	   rb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
-	   region_name = "dri2 depth buffer";
-	   break;
-
        case __DRI_BUFFER_HIZ:
-	   /* The hiz region resides in the depth renderbuffer. */
-	   rb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
-	   region_name = "dri2 hiz buffer";
-	   break;
-
        case __DRI_BUFFER_DEPTH_STENCIL:
-	   rb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
-	   region_name = "dri2 depth / stencil buffer";
-	   break;
-
        case __DRI_BUFFER_STENCIL:
-	   rb = intel_get_renderbuffer(fb, BUFFER_STENCIL);
-	   region_name = "dri2 stencil buffer";
-	   break;
-
        case __DRI_BUFFER_ACCUM:
        default:
 	   fprintf(stderr,
@@ -367,26 +314,9 @@ intel_update_renderbuffers(__DRIcontext *context, __DRIdrawable *drawable)
 	   return;
        }
 
-       if (try_separate_stencil) {
-	 intel_process_dri2_buffer_with_separate_stencil(intel, drawable,
-						         &buffers[i], rb,
-						         region_name);
-       } else {
-	 intel_process_dri2_buffer_no_separate_stencil(intel, drawable,
-						       &buffers[i], rb,
-						       region_name);
-       }
+       intel_process_dri2_buffer(intel, drawable, &buffers[i], rb, region_name);
    }
 
-   if (try_separate_stencil
-       && intel->intelScreen->dri2_has_hiz == INTEL_DRI2_HAS_HIZ_UNKNOWN) {
-      intel_verify_dri2_has_hiz(intel, drawable, &buffers, &attachments,
-				&count);
-   }
-
-   if (attachments)
-      free(attachments);
-
    driUpdateFramebufferSize(&intel->ctx, drawable);
 }
 
@@ -887,8 +817,7 @@ intelMakeCurrent(__DRIcontext * driContextPriv,
  * attached to the drawable's framebuffer. Then request the buffers with
  * DRI2GetBuffers() or DRI2GetBuffersWithFormat().
  *
- * This is called from intel_update_renderbuffers(). It is used only if either
- * the hardware or the X driver lacks separate stencil support.
+ * This is called from intel_update_renderbuffers().
  *
  * \param drawable      Drawable whose buffers are queried.
  * \param buffers       [out] List of buffers returned by DRI2 query.
@@ -899,13 +828,11 @@ intelMakeCurrent(__DRIcontext * driContextPriv,
  * \see DRI2GetBuffersWithFormat()
  */
 static void
-intel_query_dri2_buffers_no_separate_stencil(struct intel_context *intel,
-					     __DRIdrawable *drawable,
-					     __DRIbuffer **buffers,
-					     int *buffer_count)
+intel_query_dri2_buffers(struct intel_context *intel,
+			 __DRIdrawable *drawable,
+			 __DRIbuffer **buffers,
+			 int *buffer_count)
 {
-   assert(!intel->must_use_separate_stencil);
-
    __DRIscreen *screen = intel->intelScreen->driScrnPriv;
    struct gl_framebuffer *fb = drawable->driverPrivate;
 
@@ -919,13 +846,9 @@ intel_query_dri2_buffers_no_separate_stencil(struct intel_context *intel,
 
       struct intel_renderbuffer *front_rb;
       struct intel_renderbuffer *back_rb;
-      struct intel_renderbuffer *depth_rb;
-      struct intel_renderbuffer *stencil_rb;
 
       front_rb = intel_get_renderbuffer(fb, BUFFER_FRONT_LEFT);
       back_rb = intel_get_renderbuffer(fb, BUFFER_BACK_LEFT);
-      depth_rb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
-      stencil_rb = intel_get_renderbuffer(fb, BUFFER_STENCIL);
 
       if ((intel->is_front_buffer_rendering ||
 	   intel->is_front_buffer_reading ||
@@ -939,17 +862,6 @@ intel_query_dri2_buffers_no_separate_stencil(struct intel_context *intel,
 	 attachments[i++] = intel_bits_per_pixel(back_rb);
       }
 
-      if (depth_rb && stencil_rb) {
-	 attachments[i++] = __DRI_BUFFER_DEPTH_STENCIL;
-	 attachments[i++] = intel_bits_per_pixel(depth_rb);
-      } else if (depth_rb) {
-	 attachments[i++] = __DRI_BUFFER_DEPTH;
-	 attachments[i++] = intel_bits_per_pixel(depth_rb);
-      } else if (stencil_rb) {
-	 attachments[i++] = __DRI_BUFFER_STENCIL;
-	 attachments[i++] = intel_bits_per_pixel(stencil_rb);
-      }
-
       assert(i <= 2 * max_attachments);
 
       *buffers = screen->dri2.loader->getBuffersWithFormat(drawable,
@@ -970,10 +882,6 @@ intel_query_dri2_buffers_no_separate_stencil(struct intel_context *intel,
 	 attachments[i++] = __DRI_BUFFER_FRONT_LEFT;
       if (intel_get_renderbuffer(fb, BUFFER_BACK_LEFT))
 	 attachments[i++] = __DRI_BUFFER_BACK_LEFT;
-      if (intel_get_renderbuffer(fb, BUFFER_DEPTH))
-	 attachments[i++] = __DRI_BUFFER_DEPTH;
-      if (intel_get_renderbuffer(fb, BUFFER_STENCIL))
-	 attachments[i++] = __DRI_BUFFER_STENCIL;
 
       assert(i <= max_attachments);
 
@@ -994,8 +902,7 @@ intel_query_dri2_buffers_no_separate_stencil(struct intel_context *intel,
 /**
  * \brief Assign a DRI buffer's DRM region to a renderbuffer.
  *
- * This is called from intel_update_renderbuffers().  It is used only if
- * either the hardware or the X driver lacks separate stencil support.
+ * This is called from intel_update_renderbuffers().
  *
  * \par Note:
  *    DRI buffers whose attachment point is DRI2BufferStencil or
@@ -1008,16 +915,13 @@ intel_query_dri2_buffers_no_separate_stencil(struct intel_context *intel,
  * \see intel_region_alloc_for_handle()
  */
 static void
-intel_process_dri2_buffer_no_separate_stencil(struct intel_context *intel,
-					      __DRIdrawable *drawable,
-					      __DRIbuffer *buffer,
-					      struct intel_renderbuffer *rb,
-					      const char *buffer_name)
+intel_process_dri2_buffer(struct intel_context *intel,
+			  __DRIdrawable *drawable,
+			  __DRIbuffer *buffer,
+			  struct intel_renderbuffer *rb,
+			  const char *buffer_name)
 {
-   assert(!intel->must_use_separate_stencil);
-
-   struct gl_framebuffer *fb = drawable->driverPrivate;
-   struct intel_renderbuffer *depth_rb = NULL;
+   struct intel_region *region = NULL;
 
    if (!rb)
       return;
@@ -1034,472 +938,20 @@ intel_process_dri2_buffer_no_separate_stencil(struct intel_context *intel,
 	      buffer->cpp, buffer->pitch);
    }
 
-   bool identify_depth_and_stencil = false;
-   if (buffer->attachment == __DRI_BUFFER_STENCIL) {
-      struct intel_renderbuffer *depth_rb =
-	 intel_get_renderbuffer(fb, BUFFER_DEPTH);
-      identify_depth_and_stencil = depth_rb && depth_rb->mt;
-   }
-
-   if (identify_depth_and_stencil) {
-      if (unlikely(INTEL_DEBUG & DEBUG_DRI)) {
-	 fprintf(stderr, "(reusing depth buffer as stencil)\n");
-      }
-      intel_miptree_reference(&rb->mt, depth_rb->mt);
-   } else {
-      intel_miptree_release(&rb->mt);
-      struct intel_region *region =
-                   intel_region_alloc_for_handle(intel->intelScreen,
-						 buffer->cpp,
-						 drawable->w,
-						 drawable->h,
-						 buffer->pitch / buffer->cpp,
-						 buffer->name,
-						 buffer_name);
-      if (!region)
-	 return;
-
-      rb->mt = intel_miptree_create_for_region(intel,
-                                               GL_TEXTURE_2D,
-                                               intel_rb_format(rb),
-                                               region);
-      intel_region_release(&region);
-      if (!rb->mt)
-	 return;
-   }
-
-   if (buffer->attachment == __DRI_BUFFER_DEPTH_STENCIL) {
-      struct intel_renderbuffer *stencil_rb =
-	 intel_get_renderbuffer(fb, BUFFER_STENCIL);
-
-      if (!stencil_rb)
-	 return;
-
-      /* The rb passed in is the BUFFER_DEPTH attachment, and we need
-       * to associate this region to BUFFER_STENCIL as well.
-       */
-      intel_miptree_reference(&stencil_rb->mt, rb->mt);
-   }
-}
-
-/**
- * \brief Query DRI2 to obtain a DRIdrawable's buffers.
- *
- * To determine which DRI buffers to request, examine the renderbuffers
- * attached to the drawable's framebuffer. Then request the buffers with
- * DRI2GetBuffersWithFormat().
- *
- * This is called from intel_update_renderbuffers(). It is used when 1) the
- * hardware supports separate stencil and 2) the X driver's separate stencil
- * support has been verified to work or is still unknown.
- *
- * \param drawable      Drawable whose buffers are queried.
- * \param buffers       [out] List of buffers returned by DRI2 query.
- * \param buffer_count  [out] Number of buffers returned.
- * \param attachments   [out] List of pairs (attachment_point, bits_per_pixel)
- *                      that were submitted in the DRI2 query. Number of pairs
- *                      is same as buffer_count.
- *
- * \see intel_update_renderbuffers()
- * \see DRI2GetBuffersWithFormat()
- * \see enum intel_dri2_has_hiz
- */
-static void
-intel_query_dri2_buffers_with_separate_stencil(struct intel_context *intel,
-					       __DRIdrawable *drawable,
-					       __DRIbuffer **buffers,
-					       unsigned **attachments,
-					       int *count)
-{
-   assert(intel->has_separate_stencil);
-
-   __DRIscreen *screen = intel->intelScreen->driScrnPriv;
-   struct gl_framebuffer *fb = drawable->driverPrivate;
-
-   const int max_attachments = 5;
-   int i = 0;
-
-   *attachments = calloc(2 * max_attachments, sizeof(unsigned));
-   if (!*attachments) {
-      *buffers = NULL;
-      *count = 0;
-      return;
-   }
-
-   struct intel_renderbuffer *front_rb;
-   struct intel_renderbuffer *back_rb;
-   struct intel_renderbuffer *depth_rb;
-   struct intel_renderbuffer *stencil_rb;
-
-   front_rb = intel_get_renderbuffer(fb, BUFFER_FRONT_LEFT);
-   back_rb = intel_get_renderbuffer(fb, BUFFER_BACK_LEFT);
-   depth_rb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
-   stencil_rb = intel_get_renderbuffer(fb, BUFFER_STENCIL);
-
-   if ((intel->is_front_buffer_rendering ||
-	intel->is_front_buffer_reading ||
-	!back_rb) && front_rb) {
-      (*attachments)[i++] = __DRI_BUFFER_FRONT_LEFT;
-      (*attachments)[i++] = intel_bits_per_pixel(front_rb);
-   }
-
-   if (back_rb) {
-      (*attachments)[i++] = __DRI_BUFFER_BACK_LEFT;
-      (*attachments)[i++] = intel_bits_per_pixel(back_rb);
-   }
-
-   /*
-    * We request a separate stencil buffer, and perhaps a hiz buffer too, even
-    * if we do not yet know if the X driver supports it. See the comments for
-    * 'enum intel_dri2_has_hiz'.
-    */
-
-   if (depth_rb) {
-      (*attachments)[i++] = __DRI_BUFFER_DEPTH;
-      (*attachments)[i++] = intel_bits_per_pixel(depth_rb);
-
-      if (intel->vtbl.is_hiz_depth_format(intel, intel_rb_format(depth_rb))) {
-	 /* Depth and hiz buffer have same bpp. */
-	 (*attachments)[i++] = __DRI_BUFFER_HIZ;
-	 (*attachments)[i++] = intel_bits_per_pixel(depth_rb);
-      }
-   }
-
-   if (stencil_rb) {
-      assert(intel_rb_format(stencil_rb) == MESA_FORMAT_S8);
-      (*attachments)[i++] = __DRI_BUFFER_STENCIL;
-      (*attachments)[i++] = intel_bits_per_pixel(stencil_rb);
-   }
-
-   assert(i <= 2 * max_attachments);
-
-   *buffers = screen->dri2.loader->getBuffersWithFormat(drawable,
-							&drawable->w,
-							&drawable->h,
-							*attachments, i / 2,
-							count,
-							drawable->loaderPrivate);
-
-   if (!*buffers) {
-      free(*attachments);
-      *attachments = NULL;
-      *count = 0;
-   }
-}
-
-/**
- * \brief Assign a DRI buffer's DRM region to a renderbuffer.
- *
- * This is called from intel_update_renderbuffers().  It is used when 1) the
- * hardware supports separate stencil and 2) the X driver's separate stencil
- * support has been verified to work or is still unknown.
- *
- * \par Note:
- *    DRI buffers whose attachment point is DRI2BufferStencil or DRI2BufferHiz
- *    are handled as special cases.
- *
- * \param buffer_name is a human readable name, such as "dri2 front buffer",
- *        that is passed to intel_region_alloc_for_handle().
- *
- * \see intel_update_renderbuffers()
- * \see intel_region_alloc_for_handle()
- * \see enum intel_dri2_has_hiz
- */
-static void
-intel_process_dri2_buffer_with_separate_stencil(struct intel_context *intel,
-						__DRIdrawable *drawable,
-						__DRIbuffer *buffer,
-						struct intel_renderbuffer *rb,
-						const char *buffer_name)
-{
-   assert(intel->has_separate_stencil);
-   assert(buffer->attachment != __DRI_BUFFER_DEPTH_STENCIL);
-
-   if (!rb)
-      return;
-
-   /* Check if we failed to allocate the depth miptree earlier. */
-   if (buffer->attachment == __DRI_BUFFER_HIZ && rb->mt == NULL)
-     return;
-
-   /* If the renderbuffer's and DRIbuffer's regions match, then continue. */
-   if ((buffer->attachment != __DRI_BUFFER_HIZ &&
-	rb->mt &&
-	rb->mt->region &&
-	rb->mt->region->name == buffer->name) ||
-       (buffer->attachment == __DRI_BUFFER_HIZ &&
-	rb->mt &&
-	rb->mt->hiz_mt &&
-	rb->mt->hiz_mt->region->name == buffer->name)) {
-      return;
-   }
-
-   if (unlikely(INTEL_DEBUG & DEBUG_DRI)) {
-      fprintf(stderr,
-	      "attaching buffer %d, at %d, cpp %d, pitch %d\n",
-	      buffer->name, buffer->attachment,
-	      buffer->cpp, buffer->pitch);
-   }
-
-   int buffer_width;
-   int buffer_height;
-   int buffer_cpp = buffer->cpp;
-   int buffer_pitch = buffer->pitch;
-   if (buffer->attachment == __DRI_BUFFER_STENCIL) {
-      /* Stencil buffers use W tiling, a tiling format that the DRM functions
-       * don't properly account for.  Therefore, when we allocate a stencil
-       * buffer that is private to Mesa (see intel_miptree_create), we round
-       * the height and width up to the next multiple of the tile size (64x64)
-       * and then ask DRM to allocate an untiled buffer.  Consequently, the
-       * height and the width stored in the stencil buffer's region structure
-       * are always multiples of 64, even if the stencil buffer itself is
-       * smaller.
-       *
-       * To avoid inconsistencies between how we represent private buffers and
-       * buffers shared with the window system, round up the height and width
-       * for window system buffers too.
-       */
-       buffer_width = ALIGN(drawable->w, 64);
-       buffer_height = ALIGN(drawable->h, 64);
-
-       /* Versions 2.17.0 and earlier of xf86-video-intel (a.k.a. the DDX) lie
-        * and send cpp and pitch values that are two times too large for
-        * stencil buffers.  Hopefully this will be fixed in a future version
-        * of xf86-video-intel, but for now detect the bug by checking if cpp
-        * is 2, and fixing cpp and pitch if it is.
-        */
-       if (buffer_cpp == 2) {
-          buffer_cpp = 1;
-          buffer_pitch /= 2;
-       }
-   } else {
-       buffer_width = drawable->w;
-       buffer_height = drawable->h;
-   }
-
-   /* Release the buffer storage now in case we have to return early
-    * due to failure to allocate new storage.
-    */
-   if (buffer->attachment == __DRI_BUFFER_HIZ) {
-      assert(rb->mt);
-      intel_miptree_release(&rb->mt->hiz_mt);
-   } else {
-      intel_miptree_release(&rb->mt);
-   }
-
-   struct intel_region *region =
-      intel_region_alloc_for_handle(intel->intelScreen,
-				    buffer_cpp,
-				    buffer_width,
-				    buffer_height,
-				    buffer_pitch / buffer_cpp,
-				    buffer->name,
-				    buffer_name);
+   intel_miptree_release(&rb->mt);
+   region = intel_region_alloc_for_handle(intel->intelScreen,
+                                          buffer->cpp,
+                                          drawable->w,
+                                          drawable->h,
+                                          buffer->pitch / buffer->cpp,
+                                          buffer->name,
+                                          buffer_name);
    if (!region)
       return;
 
-   struct intel_mipmap_tree *mt =
-      intel_miptree_create_for_region(intel,
-				      GL_TEXTURE_2D,
-				      intel_rb_format(rb),
-				      region);
+   rb->mt = intel_miptree_create_for_region(intel,
+                                            GL_TEXTURE_2D,
+                                            intel_rb_format(rb),
+                                            region);
    intel_region_release(&region);
-
-   /* Associate buffer with new storage. */
-   if (buffer->attachment == __DRI_BUFFER_HIZ) {
-      assert(rb->mt);
-      rb->mt->hiz_mt = mt;
-   } else {
-      rb->mt = mt;
-   }
-}
-
-/**
- * \brief Verify that the X driver supports hiz and separate stencil.
- *
- * This implements the cleanup stage of the handshake described in the
- * comments for 'enum intel_dri2_has_hiz'.
- *
- * This should be called from intel_update_renderbuffers() after 1) the
- * DRIdrawable has been queried for its buffers via DRI2GetBuffersWithFormat()
- * and 2) the DRM region of each returned DRIbuffer has been assigned to the
- * appropriate intel_renderbuffer. Furthermore, this should be called *only*
- * when 1) intel_update_renderbuffers() tried to used the X driver's separate
- * stencil functionality and 2) it has not yet been determined if the X driver
- * supports separate stencil.
- *
- * If we determine that the X driver does have support, then we set
- * intel_screen.dri2_has_hiz to true and return.
- *
- * If we determine that the X driver lacks support, and we requested
- * a DRI2BufferDepth and DRI2BufferStencil, then we must remedy the mistake by
- * taking the following actions:
- *    1. Discard the framebuffer's stencil and depth renderbuffers.
- *    2. Create a combined depth/stencil renderbuffer and attach
- *       it to the framebuffer's depth and stencil attachment points.
- *    3. Query the drawable for a new set of buffers, which consists of the
- *       originally requested set plus DRI2BufferDepthStencil.
- *    4. Assign the DRI2BufferDepthStencil's DRM region to the new
- *       depth/stencil renderbuffer.
- *
- * \pre intel->intelScreen->dri2_has_hiz == INTEL_DRI2_HAS_HIZ_UNKNOWN
- *
- * \param drawable      Drawable whose buffers were queried.
- *
- * \param buffers       [in/out] As input, the buffer list returned by the
- *                      original DRI2 query. As output, the current buffer
- *                      list, which may have been altered by a new DRI2 query.
- *
- * \param attachments   [in/out] As input, the attachment list submitted
- *                      in the original DRI2 query. As output, the attachment
- *                      list that was submitted in the DRI2 query that
- *                      obtained the current buffer list, as returned in the
- *                      output parameter \c buffers.  (Note: If no new query
- *                      was made, then the list remains unaltered).
- *
- * \param count         [out] Number of buffers in the current buffer list, as
- *                      returned in the output parameter \c buffers.
- *
- * \see enum intel_dri2_has_hiz
- * \see struct intel_screen::dri2_has_hiz
- * \see intel_update_renderbuffers
- */
-static void
-intel_verify_dri2_has_hiz(struct intel_context *intel,
-			  __DRIdrawable *drawable,
-			  __DRIbuffer **buffers,
-			  unsigned **attachments,
-			  int *count)
-{
-   assert(intel->intelScreen->dri2_has_hiz == INTEL_DRI2_HAS_HIZ_UNKNOWN);
-
-   struct gl_framebuffer *fb = drawable->driverPrivate;
-   struct intel_renderbuffer *stencil_rb =
-      intel_get_renderbuffer(fb, BUFFER_STENCIL);
-
-   if (stencil_rb) {
-      /*
-       * We requested a DRI2BufferStencil without knowing if the X driver
-       * supports it. Now, check if X handled the request correctly and clean
-       * up if it did not. (See comments for 'enum intel_dri2_has_hiz').
-       */
-      struct intel_renderbuffer *depth_rb =
-	 intel_get_renderbuffer(fb, BUFFER_DEPTH);
-      assert(intel_rb_format(stencil_rb) == MESA_FORMAT_S8);
-      assert(depth_rb && intel_rb_format(depth_rb) == MESA_FORMAT_X8_Z24);
-
-      if (stencil_rb->mt->region->tiling == I915_TILING_NONE) {
-	 /*
-	  * The stencil buffer is actually W tiled. The region's tiling is
-	  * I915_TILING_NONE, however, because the GTT is incapable of W
-	  * fencing.
-	  */
-	 intel->intelScreen->dri2_has_hiz = INTEL_DRI2_HAS_HIZ_TRUE;
-	 return;
-      } else {
-	 /*
-	  * Oops... the screen doesn't support separate stencil. Discard the
-	  * separate depth and stencil buffers and replace them with
-	  * a combined depth/stencil buffer. Discard the hiz buffer too.
-	  */
-	 intel->intelScreen->dri2_has_hiz = INTEL_DRI2_HAS_HIZ_FALSE;
-	 if (intel->must_use_separate_stencil) {
-	    _mesa_problem(&intel->ctx,
-			  "intel_context requires separate stencil, but the "
-			  "DRIscreen does not support it. You may need to "
-			  "upgrade the Intel X driver to 2.16.0");
-	    abort();
-	 }
-
-	 /* 1. Discard depth and stencil renderbuffers. */
-	 _mesa_remove_renderbuffer(fb, BUFFER_DEPTH);
-	 depth_rb = NULL;
-	 _mesa_remove_renderbuffer(fb, BUFFER_STENCIL);
-	 stencil_rb = NULL;
-
-	 /* 2. Create new depth/stencil renderbuffer. */
-	 struct intel_renderbuffer *depth_stencil_rb =
-	    intel_create_renderbuffer(MESA_FORMAT_S8_Z24);
-	 _mesa_add_renderbuffer(fb, BUFFER_DEPTH, &depth_stencil_rb->Base.Base);
-	 _mesa_add_renderbuffer(fb, BUFFER_STENCIL, &depth_stencil_rb->Base.Base);
-
-	 /* 3. Append DRI2BufferDepthStencil to attachment list. */
-	 int old_count = *count;
-	 unsigned int *old_attachments = *attachments;
-	 *count = old_count + 1;
-	 *attachments = malloc(2 * (*count) * sizeof(unsigned));
-	 memcpy(*attachments, old_attachments, 2 * old_count * sizeof(unsigned));
-	 free(old_attachments);
-	 (*attachments)[2 * old_count + 0] = __DRI_BUFFER_DEPTH_STENCIL;
-	 (*attachments)[2 * old_count + 1] = intel_bits_per_pixel(depth_stencil_rb);
-
-	 /* 4. Request new set of DRI2 attachments. */
-	 __DRIscreen *screen = intel->intelScreen->driScrnPriv;
-	 *buffers = screen->dri2.loader->getBuffersWithFormat(drawable,
-							      &drawable->w,
-							      &drawable->h,
-							      *attachments,
-							      *count,
-							      count,
-							      drawable->loaderPrivate);
-	 if (!*buffers)
-	    return;
-
-	 /*
-	  * I don't know how to recover from the failure assertion below.
-	  * Rather than fail gradually and unexpectedly, we should just die
-	  * now.
-	  */
-	 assert(*count == old_count + 1);
-
-	 /* 5. Assign the DRI buffer's DRM region to the its renderbuffers. */
-	 __DRIbuffer *depth_stencil_buffer = NULL;
-	 for (int i = 0; i < *count; ++i) {
-	    if ((*buffers)[i].attachment == __DRI_BUFFER_DEPTH_STENCIL) {
-	       depth_stencil_buffer = &(*buffers)[i];
-	       break;
-	    }
-	 }
-	 struct intel_region *region =
-	    intel_region_alloc_for_handle(intel->intelScreen,
-					  depth_stencil_buffer->cpp,
-					  drawable->w,
-					  drawable->h,
-					  depth_stencil_buffer->pitch
-					     / depth_stencil_buffer->cpp,
-					  depth_stencil_buffer->name,
-					  "dri2 depth / stencil buffer");
-	 if (!region)
-	    return;
-
-	 struct intel_mipmap_tree *mt =
-	       intel_miptree_create_for_region(intel,
-	                                       GL_TEXTURE_2D,
-	                                       intel_rb_format(depth_stencil_rb),
-	                                       region);
-	 intel_region_release(&region);
-	 if (!mt)
-	    return;
-
-	 intel_miptree_reference(&intel_get_renderbuffer(fb, BUFFER_DEPTH)->mt, mt);
-	 intel_miptree_reference(&intel_get_renderbuffer(fb, BUFFER_STENCIL)->mt, mt);
-	 intel_miptree_release(&mt);
-      }
-   }
-
-   if (intel_framebuffer_has_hiz(fb)) {
-      /*
-       * In the future, the driver may advertise a GL config with hiz
-       * compatible depth bits and 0 stencil bits (for example, when the
-       * driver gains support for float32 depth buffers). When that day comes,
-       * here we need to verify that the X driver does in fact support hiz and
-       * clean up if it doesn't.
-       *
-       * Presently, however, no verification or clean up is necessary, and
-       * execution should not reach here. If the framebuffer still has a hiz
-       * region, then we have already set dri2_has_hiz to true after
-       * confirming above that the stencil buffer is W tiled.
-       */
-      assert(0);
-   }
 }