diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/gallium/drivers/vc4/vc4_qir_schedule.c | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/src/gallium/drivers/vc4/vc4_qir_schedule.c b/src/gallium/drivers/vc4/vc4_qir_schedule.c index 69bd0dd623e..6b7efdb3c0e 100644 --- a/src/gallium/drivers/vc4/vc4_qir_schedule.c +++ b/src/gallium/drivers/vc4/vc4_qir_schedule.c @@ -297,16 +297,48 @@ calculate_forward_deps(struct vc4_compile *c, void *mem_ctx, case QOP_TEX_R: case QOP_TEX_B: case QOP_TEX_DIRECT: - /* If the texture coordinate fifo is full, - * block this on the last QOP_TEX_RESULT. + /* 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. */ if (state.tfreq_count == 8) { block_until_tex_result(&state, n); } - /* If the texture result fifo is full, block - * adding any more to it until the last - * QOP_TEX_RESULT. + /* From the VC4 spec: + * + * "Since the maximum number of texture requests + * in the input (TFREQ) FIFO is four lots of (s, + * t) data, the output (TFRCV) FIFO is sized to + * holds four lots of max-size color data per + * QPU. For non-float color, reads are packed + * RGBA8888 data (one read per pixel). For 16-bit + * float color, two reads are necessary per + * pixel, with reads packed as RG1616 then + * BA1616. So per QPU there are eight color slots + * in the TFRCV FIFO." + * + * If the texture result fifo is full, block adding + * any more to it until the last QOP_TEX_RESULT. */ if (inst->op == QOP_TEX_S || inst->op == QOP_TEX_DIRECT) { |