[Mesa-dev] [PATCH v2 01/64] i965: Drop the maximum 3D texture size to 512 on Sandy Bridge

[Jason Ekstrand]

The RenderTargetViewExtent field of RENDER_SURFACE_STATE is supposed to be
set to the depth of a 3-D texture when rendering.  Unfortunatley, that
field is only 9 bits on Sandy Bridge and prior so we can't actually bind
a 3-D texturing for rendering if it has depth > 512.  On Ivy Bridge, this
field was bumpped to 11 bits so we can go all the way up to 2048.  On Iron
Lake and prior, we don't support layered rendering and we use OffsetX/Y
hacks to render to particular layers so 2048 is ok there too.

Cc: "11.1 11.2 12.0" <mesa-stable at lists.freedesktop.org>
Cc: Ian Romanick <idr at freedesktop.org>

---
 src/mesa/drivers/dri/i965/brw_context.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index f7c7874..c7a66cb 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -467,7 +467,16 @@ brw_initialize_context_constants(struct brw_context *brw)
    ctx->Const.MaxImageUnits = MAX_IMAGE_UNITS;
    ctx->Const.MaxRenderbufferSize = 8192;
    ctx->Const.MaxTextureLevels = MIN2(14 /* 8192 */, MAX_TEXTURE_LEVELS);
-   ctx->Const.Max3DTextureLevels = 12; /* 2048 */
+
+   /* On Sandy Bridge and prior, the "Render Target View Extent" field of
+    * RENDER_SURFACE_STATE is only 9 bits so the largest 3-D texture we can do
+    * a layered render into has a depth of 512.  On Iron Lake and earlier, we
+    * don't support layered rendering and we use manual offsetting to render
+    * into the different layers so this doesn't matter.  On Sandy Bridge,
+    * however, we do support layered rendering so this is a problem.
+    */
+   ctx->Const.Max3DTextureLevels = brw->gen == 6 ? 10 /* 512 */ : 12; /* 2048 */
+
    ctx->Const.MaxCubeTextureLevels = 14; /* 8192 */
    ctx->Const.MaxArrayTextureLayers = brw->gen >= 7 ? 2048 : 512;
    ctx->Const.MaxTextureMbytes = 1536;
-- 
2.5.0.400.gff86faf