+ /* It is not yet clear what tiler_meta means or how it's
+ * calculated, but we can tell the lower 32-bits are a
+ * (monotonically increasing?) function of tile count and
+ * geometry complexity; I suspect it defines a memory size of
+ * some kind? for the tiler. It's really unclear at the
+ * moment... but to add to the confusion, the hardware is happy
+ * enough to accept a zero in this field, so we don't even have
+ * to worry about it right now.
+ *
+ * The byte (just after the 32-bit mark) is much more
+ * interesting. The higher nibble I've only ever seen as 0xF,
+ * but the lower one I've seen as 0x0 or 0xF, and it's not
+ * obvious what the difference is. But what -is- obvious is
+ * that when the lower nibble is zero, performance is severely
+ * degraded compared to when the lower nibble is set.
+ * Evidently, that nibble enables some sort of fast path,
+ * perhaps relating to caching or tile flush? Regardless, at
+ * this point there's no clear reason not to set it, aside from
+ * substantially increased memory requirements (of the misc_0
+ * buffer) */
+
+ .tiler_meta = ((uint64_t) 0xff << 32) | 0x0,