+ switch (inst->dst.file) {
+ case QFILE_TEX_S_DIRECT:
+ case QFILE_TEX_S:
+ case QFILE_TEX_T:
+ case QFILE_TEX_R:
+ case QFILE_TEX_B:
+ /* From the VC4 spec:
+ *
+ * "The TFREQ input FIFO holds two full lots of s,
+ * t, r, b data, plus associated setup data, per
+ * QPU, that is, there are eight data slots. For
+ * each texture request, slots are only consumed
+ * for the components of s, t, r, and b actually
+ * written. Thus the FIFO can hold four requests
+ * of just (s, t) data, or eight requests of just
+ * s data (for direct addressed data lookups).
+ *
+ * Note that there is one FIFO per QPU, and the
+ * FIFO has no concept of threads - that is,
+ * multi-threaded shaders must be careful to use
+ * only 1/2 the FIFO depth before reading
+ * back. Multi-threaded programs must also
+ * therefore always thread switch on texture
+ * fetch as the other thread may have data
+ * waiting in the FIFO."
+ *
+ * If the texture coordinate fifo is full, block this
+ * on the last QOP_TEX_RESULT.