1 /*
2 * Copyright (C) 2014 Rob Clark <robclark@freedesktop.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 * SOFTWARE.
22 *
23 * Authors:
24 * Rob Clark <robclark@freedesktop.org>
25 */
26
27 #include "pipe/p_screen.h"
28 #include "pipe/p_state.h"
29 #include "tgsi/tgsi_dump.h"
30 #include "tgsi/tgsi_parse.h"
31 #include "util/format/u_format.h"
32 #include "util/u_inlines.h"
33 #include "util/u_memory.h"
34 #include "util/u_string.h"
35
36 #include "nir/tgsi_to_nir.h"
37 #include "nir_serialize.h"
38
39 #include "freedreno_context.h"
40 #include "freedreno_util.h"
41
42 #include "ir3/ir3_cache.h"
43 #include "ir3/ir3_compiler.h"
44 #include "ir3/ir3_gallium.h"
45 #include "ir3/ir3_nir.h"
46 #include "ir3/ir3_shader.h"
47
48 /**
49 * The hardware cso for shader state
50 *
51 * Initially just a container for the ir3_shader, but this is where we'll
52 * plumb in async compile.
53 */
54 struct ir3_shader_state {
55 struct ir3_shader *shader;
56
57 /* Fence signalled when async compile is completed: */
58 struct util_queue_fence ready;
59 };
60
61 /**
62 * Should initial variants be compiled synchronously?
63 *
64 * The only case where util_debug_message() is used in the initial-variants
65 * path is with FD_MESA_DEBUG=shaderdb. So if either debug is disabled (ie.
66 * debug.debug_message==NULL), or shaderdb stats are not enabled, we can
67 * compile the initial shader variant asynchronously.
68 */
69 static bool
initial_variants_synchronous(struct fd_context * ctx)70 initial_variants_synchronous(struct fd_context *ctx)
71 {
72 return unlikely(ctx->debug.debug_message) || FD_DBG(SHADERDB) ||
73 FD_DBG(SERIALC);
74 }
75
76 static void
dump_shader_info(struct ir3_shader_variant * v,struct util_debug_callback * debug)77 dump_shader_info(struct ir3_shader_variant *v,
78 struct util_debug_callback *debug)
79 {
80 if (!FD_DBG(SHADERDB))
81 return;
82
83 util_debug_message(
84 debug, SHADER_INFO,
85 "%s shader: %u inst, %u nops, %u non-nops, %u mov, %u cov, "
86 "%u dwords, %u last-baryf, %u half, %u full, %u constlen, "
87 "%u cat0, %u cat1, %u cat2, %u cat3, %u cat4, %u cat5, %u cat6, %u cat7, "
88 "%u stp, %u ldp, %u sstall, %u (ss), %u systall, %u (sy), %d waves, "
89 "%d loops\n",
90 ir3_shader_stage(v), v->info.instrs_count, v->info.nops_count,
91 v->info.instrs_count - v->info.nops_count, v->info.mov_count,
92 v->info.cov_count, v->info.sizedwords, v->info.last_baryf,
93 v->info.max_half_reg + 1, v->info.max_reg + 1, v->constlen,
94 v->info.instrs_per_cat[0], v->info.instrs_per_cat[1],
95 v->info.instrs_per_cat[2], v->info.instrs_per_cat[3],
96 v->info.instrs_per_cat[4], v->info.instrs_per_cat[5],
97 v->info.instrs_per_cat[6], v->info.instrs_per_cat[7],
98 v->info.stp_count, v->info.ldp_count, v->info.sstall,
99 v->info.ss, v->info.systall, v->info.sy, v->info.max_waves, v->loops);
100 }
101
102 static void
upload_shader_variant(struct ir3_shader_variant * v)103 upload_shader_variant(struct ir3_shader_variant *v)
104 {
105 struct ir3_compiler *compiler = v->compiler;
106
107 assert(!v->bo);
108
109 v->bo =
110 fd_bo_new(compiler->dev, v->info.size, FD_BO_NOMAP,
111 "%s:%s", ir3_shader_stage(v), v->name);
112
113 /* Always include shaders in kernel crash dumps. */
114 fd_bo_mark_for_dump(v->bo);
115
116 fd_bo_upload(v->bo, v->bin, v->info.size);
117 }
118
119 struct ir3_shader_variant *
ir3_shader_variant(struct ir3_shader * shader,struct ir3_shader_key key,bool binning_pass,struct util_debug_callback * debug)120 ir3_shader_variant(struct ir3_shader *shader, struct ir3_shader_key key,
121 bool binning_pass, struct util_debug_callback *debug)
122 {
123 struct ir3_shader_variant *v;
124 bool created = false;
125
126 /* Some shader key values may not be used by a given ir3_shader (for
127 * example, fragment shader saturates in the vertex shader), so clean out
128 * those flags to avoid recompiling.
129 */
130 ir3_key_clear_unused(&key, shader);
131
132 v = ir3_shader_get_variant(shader, &key, binning_pass, false, &created);
133
134 if (created) {
135 if (shader->initial_variants_done) {
136 perf_debug_message(debug, SHADER_INFO,
137 "%s shader: recompiling at draw time: global "
138 "0x%08x, vfsamples %x/%x, astc %x/%x\n",
139 ir3_shader_stage(v), key.global, key.vsamples,
140 key.fsamples, key.vastc_srgb, key.fastc_srgb);
141 }
142
143 dump_shader_info(v, debug);
144 upload_shader_variant(v);
145
146 if (v->binning) {
147 upload_shader_variant(v->binning);
148 dump_shader_info(v->binning, debug);
149 }
150 }
151
152 return v;
153 }
154
155 static void
copy_stream_out(struct ir3_stream_output_info * i,const struct pipe_stream_output_info * p)156 copy_stream_out(struct ir3_stream_output_info *i,
157 const struct pipe_stream_output_info *p)
158 {
159 STATIC_ASSERT(ARRAY_SIZE(i->stride) == ARRAY_SIZE(p->stride));
160 STATIC_ASSERT(ARRAY_SIZE(i->output) == ARRAY_SIZE(p->output));
161
162 i->num_outputs = p->num_outputs;
163 for (int n = 0; n < ARRAY_SIZE(i->stride); n++)
164 i->stride[n] = p->stride[n];
165
166 for (int n = 0; n < ARRAY_SIZE(i->output); n++) {
167 i->output[n].register_index = p->output[n].register_index;
168 i->output[n].start_component = p->output[n].start_component;
169 i->output[n].num_components = p->output[n].num_components;
170 i->output[n].output_buffer = p->output[n].output_buffer;
171 i->output[n].dst_offset = p->output[n].dst_offset;
172 i->output[n].stream = p->output[n].stream;
173 }
174 }
175
176 static void
create_initial_variants(struct ir3_shader_state * hwcso,struct util_debug_callback * debug)177 create_initial_variants(struct ir3_shader_state *hwcso,
178 struct util_debug_callback *debug)
179 {
180 struct ir3_shader *shader = hwcso->shader;
181 struct ir3_compiler *compiler = shader->compiler;
182 nir_shader *nir = shader->nir;
183
184 /* Compile standard variants immediately to try to avoid draw-time stalls
185 * to run the compiler.
186 */
187 struct ir3_shader_key key = {
188 .tessellation = IR3_TESS_NONE,
189 .ucp_enables = MASK(nir->info.clip_distance_array_size),
190 .msaa = true,
191 };
192
193 switch (nir->info.stage) {
194 case MESA_SHADER_TESS_EVAL:
195 key.tessellation = ir3_tess_mode(nir->info.tess._primitive_mode);
196 break;
197
198 case MESA_SHADER_TESS_CTRL:
199 /* The primitive_mode field, while it exists for TCS, is not
200 * populated (since separable shaders between TCS/TES are legal,
201 * so TCS wouldn't have access to TES's declaration). Make a
202 * guess so that we shader-db something plausible for TCS.
203 */
204 if (nir->info.outputs_written & VARYING_BIT_TESS_LEVEL_INNER)
205 key.tessellation = IR3_TESS_TRIANGLES;
206 else
207 key.tessellation = IR3_TESS_ISOLINES;
208 break;
209
210 case MESA_SHADER_GEOMETRY:
211 key.has_gs = true;
212 break;
213
214 default:
215 break;
216 }
217
218 key.safe_constlen = false;
219 struct ir3_shader_variant *v = ir3_shader_variant(shader, key, false, debug);
220 if (!v)
221 return;
222
223 if (v->constlen > compiler->max_const_safe) {
224 key.safe_constlen = true;
225 ir3_shader_variant(shader, key, false, debug);
226 }
227
228 /* For vertex shaders, also compile initial binning pass shader: */
229 if (nir->info.stage == MESA_SHADER_VERTEX) {
230 key.safe_constlen = false;
231 v = ir3_shader_variant(shader, key, true, debug);
232 if (!v)
233 return;
234
235 if (v->constlen > compiler->max_const_safe) {
236 key.safe_constlen = true;
237 ir3_shader_variant(shader, key, true, debug);
238 }
239 }
240
241 shader->initial_variants_done = true;
242 }
243
244 static void
create_initial_variants_async(void * job,void * gdata,int thread_index)245 create_initial_variants_async(void *job, void *gdata, int thread_index)
246 {
247 struct ir3_shader_state *hwcso = job;
248 struct util_debug_callback debug = {};
249
250 create_initial_variants(hwcso, &debug);
251 }
252
253 static void
create_initial_compute_variants_async(void * job,void * gdata,int thread_index)254 create_initial_compute_variants_async(void *job, void *gdata, int thread_index)
255 {
256 struct ir3_shader_state *hwcso = job;
257 struct ir3_shader *shader = hwcso->shader;
258 struct util_debug_callback debug = {};
259 static struct ir3_shader_key key; /* static is implicitly zeroed */
260
261 ir3_shader_variant(shader, key, false, &debug);
262 shader->initial_variants_done = true;
263 }
264
265 /* a bit annoying that compute-shader and normal shader state objects
266 * aren't a bit more aligned.
267 */
268 void *
ir3_shader_compute_state_create(struct pipe_context * pctx,const struct pipe_compute_state * cso)269 ir3_shader_compute_state_create(struct pipe_context *pctx,
270 const struct pipe_compute_state *cso)
271 {
272 struct fd_context *ctx = fd_context(pctx);
273
274 /* req_input_mem will only be non-zero for cl kernels (ie. clover).
275 * This isn't a perfect test because I guess it is possible (but
276 * uncommon) for none for the kernel parameters to be a global,
277 * but ctx->set_global_bindings() can't fail, so this is the next
278 * best place to fail if we need a newer version of kernel driver:
279 */
280 if ((cso->req_input_mem > 0) &&
281 fd_device_version(ctx->dev) < FD_VERSION_BO_IOVA) {
282 return NULL;
283 }
284
285 struct ir3_compiler *compiler = ctx->screen->compiler;
286 nir_shader *nir;
287
288 if (cso->ir_type == PIPE_SHADER_IR_NIR) {
289 /* we take ownership of the reference: */
290 nir = (nir_shader *)cso->prog;
291 } else if (cso->ir_type == PIPE_SHADER_IR_NIR_SERIALIZED) {
292 const nir_shader_compiler_options *options =
293 ir3_get_compiler_options(compiler);
294 const struct pipe_binary_program_header *hdr = cso->prog;
295 struct blob_reader reader;
296
297 blob_reader_init(&reader, hdr->blob, hdr->num_bytes);
298 nir = nir_deserialize(NULL, options, &reader);
299
300 ir3_finalize_nir(compiler, nir);
301 } else {
302 assert(cso->ir_type == PIPE_SHADER_IR_TGSI);
303 if (ir3_shader_debug & IR3_DBG_DISASM) {
304 tgsi_dump(cso->prog, 0);
305 }
306 nir = tgsi_to_nir(cso->prog, pctx->screen, false);
307 }
308
309 struct ir3_shader *shader =
310 ir3_shader_from_nir(compiler, nir, &(struct ir3_shader_options){
311 /* TODO: force to single on a6xx with legacy
312 * ballot extension that uses 64-bit masks
313 */
314 .api_wavesize = IR3_SINGLE_OR_DOUBLE,
315 .real_wavesize = IR3_SINGLE_OR_DOUBLE,
316 }, NULL);
317 shader->cs.req_input_mem = align(cso->req_input_mem, 4) / 4; /* byte->dword */
318 shader->cs.req_local_mem = cso->req_local_mem;
319
320 struct ir3_shader_state *hwcso = calloc(1, sizeof(*hwcso));
321
322 util_queue_fence_init(&hwcso->ready);
323 hwcso->shader = shader;
324
325 /* Immediately compile a standard variant. We have so few variants in our
326 * shaders, that doing so almost eliminates draw-time recompiles. (This
327 * is also how we get data from shader-db's ./run)
328 */
329
330 if (initial_variants_synchronous(ctx)) {
331 static struct ir3_shader_key key; /* static is implicitly zeroed */
332 ir3_shader_variant(shader, key, false, &ctx->debug);
333 shader->initial_variants_done = true;
334 } else {
335 struct fd_screen *screen = ctx->screen;
336 util_queue_add_job(&screen->compile_queue, hwcso, &hwcso->ready,
337 create_initial_compute_variants_async, NULL, 0);
338 }
339
340 return hwcso;
341 }
342
343 void *
ir3_shader_state_create(struct pipe_context * pctx,const struct pipe_shader_state * cso)344 ir3_shader_state_create(struct pipe_context *pctx,
345 const struct pipe_shader_state *cso)
346 {
347 struct fd_context *ctx = fd_context(pctx);
348 struct ir3_compiler *compiler = ctx->screen->compiler;
349 struct ir3_shader_state *hwcso = calloc(1, sizeof(*hwcso));
350
351 /*
352 * Convert to nir (if necessary):
353 */
354
355 nir_shader *nir;
356 if (cso->type == PIPE_SHADER_IR_NIR) {
357 /* we take ownership of the reference: */
358 nir = cso->ir.nir;
359 } else {
360 assert(cso->type == PIPE_SHADER_IR_TGSI);
361 if (ir3_shader_debug & IR3_DBG_DISASM) {
362 tgsi_dump(cso->tokens, 0);
363 }
364 nir = tgsi_to_nir(cso->tokens, pctx->screen, false);
365 }
366
367 /*
368 * Create ir3_shader:
369 *
370 * This part is cheap, it doesn't compile initial variants
371 */
372
373 struct ir3_stream_output_info stream_output = {};
374 copy_stream_out(&stream_output, &cso->stream_output);
375
376 hwcso->shader =
377 ir3_shader_from_nir(compiler, nir, &(struct ir3_shader_options){
378 /* TODO: force to single on a6xx with legacy
379 * ballot extension that uses 64-bit masks
380 */
381 .api_wavesize = IR3_SINGLE_OR_DOUBLE,
382 .real_wavesize = IR3_SINGLE_OR_DOUBLE,
383 },
384 &stream_output);
385
386 /*
387 * Create initial variants to avoid draw-time stalls. This is
388 * normally done asynchronously, unless debug is enabled (which
389 * will be the case for shader-db)
390 */
391
392 util_queue_fence_init(&hwcso->ready);
393
394 if (initial_variants_synchronous(ctx)) {
395 create_initial_variants(hwcso, &ctx->debug);
396 } else {
397 util_queue_add_job(&ctx->screen->compile_queue, hwcso, &hwcso->ready,
398 create_initial_variants_async, NULL, 0);
399 }
400
401 return hwcso;
402 }
403
404 void
ir3_shader_state_delete(struct pipe_context * pctx,void * _hwcso)405 ir3_shader_state_delete(struct pipe_context *pctx, void *_hwcso)
406 {
407 struct fd_context *ctx = fd_context(pctx);
408 struct fd_screen *screen = ctx->screen;
409 struct ir3_shader_state *hwcso = _hwcso;
410 struct ir3_shader *so = hwcso->shader;
411
412 ir3_cache_invalidate(ctx->shader_cache, hwcso);
413
414 /* util_queue_drop_job() guarantees that either:
415 * 1) job did not execute
416 * 2) job completed
417 *
418 * In either case the fence is signaled
419 */
420 util_queue_drop_job(&screen->compile_queue, &hwcso->ready);
421
422 /* free the uploaded shaders, since this is handled outside of the
423 * shared ir3 code (ie. not used by turnip):
424 */
425 for (struct ir3_shader_variant *v = so->variants; v; v = v->next) {
426 fd_bo_del(v->bo);
427 v->bo = NULL;
428
429 if (v->binning && v->binning->bo) {
430 fd_bo_del(v->binning->bo);
431 v->binning->bo = NULL;
432 }
433 }
434
435 ir3_shader_destroy(so);
436 util_queue_fence_destroy(&hwcso->ready);
437 free(hwcso);
438 }
439
440 struct ir3_shader *
ir3_get_shader(struct ir3_shader_state * hwcso)441 ir3_get_shader(struct ir3_shader_state *hwcso)
442 {
443 if (!hwcso)
444 return NULL;
445
446 struct ir3_shader *shader = hwcso->shader;
447 perf_time (1000, "waited for %s:%s:%s variants",
448 _mesa_shader_stage_to_abbrev(shader->type),
449 shader->nir->info.name,
450 shader->nir->info.label) {
451 /* wait for initial variants to compile: */
452 util_queue_fence_wait(&hwcso->ready);
453 }
454
455 return shader;
456 }
457
458 struct shader_info *
ir3_get_shader_info(struct ir3_shader_state * hwcso)459 ir3_get_shader_info(struct ir3_shader_state *hwcso)
460 {
461 if (!hwcso)
462 return NULL;
463 return &hwcso->shader->nir->info;
464 }
465
466 /* fixup dirty shader state in case some "unrelated" (from the state-
467 * tracker's perspective) state change causes us to switch to a
468 * different variant.
469 */
470 void
ir3_fixup_shader_state(struct pipe_context * pctx,struct ir3_shader_key * key)471 ir3_fixup_shader_state(struct pipe_context *pctx, struct ir3_shader_key *key)
472 {
473 struct fd_context *ctx = fd_context(pctx);
474
475 if (!ir3_shader_key_equal(ctx->last.key, key)) {
476 if (ir3_shader_key_changes_fs(ctx->last.key, key)) {
477 fd_context_dirty_shader(ctx, PIPE_SHADER_FRAGMENT,
478 FD_DIRTY_SHADER_PROG);
479 }
480
481 if (ir3_shader_key_changes_vs(ctx->last.key, key)) {
482 fd_context_dirty_shader(ctx, PIPE_SHADER_VERTEX, FD_DIRTY_SHADER_PROG);
483 }
484
485 /* NOTE: currently only a6xx has gs/tess, but needs no
486 * gs/tess specific lowering.
487 */
488
489 *ctx->last.key = *key;
490 }
491 }
492
493 static char *
ir3_screen_finalize_nir(struct pipe_screen * pscreen,void * nir)494 ir3_screen_finalize_nir(struct pipe_screen *pscreen, void *nir)
495 {
496 struct fd_screen *screen = fd_screen(pscreen);
497
498 ir3_nir_lower_io_to_temporaries(nir);
499 ir3_finalize_nir(screen->compiler, nir);
500
501 return NULL;
502 }
503
504 static void
ir3_set_max_shader_compiler_threads(struct pipe_screen * pscreen,unsigned max_threads)505 ir3_set_max_shader_compiler_threads(struct pipe_screen *pscreen,
506 unsigned max_threads)
507 {
508 struct fd_screen *screen = fd_screen(pscreen);
509
510 /* This function doesn't allow a greater number of threads than
511 * the queue had at its creation.
512 */
513 util_queue_adjust_num_threads(&screen->compile_queue, max_threads);
514 }
515
516 static bool
ir3_is_parallel_shader_compilation_finished(struct pipe_screen * pscreen,void * shader,enum pipe_shader_type shader_type)517 ir3_is_parallel_shader_compilation_finished(struct pipe_screen *pscreen,
518 void *shader,
519 enum pipe_shader_type shader_type)
520 {
521 struct ir3_shader_state *hwcso = (struct ir3_shader_state *)shader;
522
523 return util_queue_fence_is_signalled(&hwcso->ready);
524 }
525
526 void
ir3_prog_init(struct pipe_context * pctx)527 ir3_prog_init(struct pipe_context *pctx)
528 {
529 pctx->create_vs_state = ir3_shader_state_create;
530 pctx->delete_vs_state = ir3_shader_state_delete;
531
532 pctx->create_tcs_state = ir3_shader_state_create;
533 pctx->delete_tcs_state = ir3_shader_state_delete;
534
535 pctx->create_tes_state = ir3_shader_state_create;
536 pctx->delete_tes_state = ir3_shader_state_delete;
537
538 pctx->create_gs_state = ir3_shader_state_create;
539 pctx->delete_gs_state = ir3_shader_state_delete;
540
541 pctx->create_fs_state = ir3_shader_state_create;
542 pctx->delete_fs_state = ir3_shader_state_delete;
543 }
544
545 void
ir3_screen_init(struct pipe_screen * pscreen)546 ir3_screen_init(struct pipe_screen *pscreen)
547 {
548 struct fd_screen *screen = fd_screen(pscreen);
549
550 screen->compiler = ir3_compiler_create(screen->dev, screen->dev_id,
551 &(struct ir3_compiler_options) {});
552
553 /* TODO do we want to limit things to # of fast cores, or just limit
554 * based on total # of both big and little cores. The little cores
555 * tend to be in-order and probably much slower for compiling than
556 * big cores. OTOH if they are sitting idle, maybe it is useful to
557 * use them?
558 */
559 unsigned num_threads = sysconf(_SC_NPROCESSORS_ONLN) - 1;
560
561 /* Create at least one thread - even on single core CPU systems. */
562 num_threads = MAX2(1, num_threads);
563
564 util_queue_init(&screen->compile_queue, "ir3q", 64, num_threads,
565 UTIL_QUEUE_INIT_RESIZE_IF_FULL |
566 UTIL_QUEUE_INIT_SET_FULL_THREAD_AFFINITY, NULL);
567
568 pscreen->finalize_nir = ir3_screen_finalize_nir;
569 pscreen->set_max_shader_compiler_threads =
570 ir3_set_max_shader_compiler_threads;
571 pscreen->is_parallel_shader_compilation_finished =
572 ir3_is_parallel_shader_compilation_finished;
573 }
574
575 void
ir3_screen_fini(struct pipe_screen * pscreen)576 ir3_screen_fini(struct pipe_screen *pscreen)
577 {
578 struct fd_screen *screen = fd_screen(pscreen);
579
580 util_queue_destroy(&screen->compile_queue);
581 ir3_compiler_destroy(screen->compiler);
582 screen->compiler = NULL;
583 }
584
585 void
ir3_update_max_tf_vtx(struct fd_context * ctx,const struct ir3_shader_variant * v)586 ir3_update_max_tf_vtx(struct fd_context *ctx,
587 const struct ir3_shader_variant *v)
588 {
589 struct fd_streamout_stateobj *so = &ctx->streamout;
590 const struct ir3_stream_output_info *info = &v->stream_output;
591 uint32_t maxvtxcnt = 0x7fffffff;
592
593 if (v->stream_output.num_outputs == 0)
594 maxvtxcnt = 0;
595 if (so->num_targets == 0)
596 maxvtxcnt = 0;
597
598 /* offset to write to is:
599 *
600 * total_vtxcnt = vtxcnt + offsets[i]
601 * offset = total_vtxcnt * stride[i]
602 *
603 * offset = vtxcnt * stride[i] ; calculated in shader
604 * + offsets[i] * stride[i] ; calculated at emit_tfbos()
605 *
606 * assuming for each vtx, each target buffer will have data written
607 * up to 'offset + stride[i]', that leaves maxvtxcnt as:
608 *
609 * buffer_size = (maxvtxcnt * stride[i]) + stride[i]
610 * maxvtxcnt = (buffer_size - stride[i]) / stride[i]
611 *
612 * but shader is actually doing a less-than (rather than less-than-
613 * equal) check, so we can drop the -stride[i].
614 *
615 * TODO is assumption about `offset + stride[i]` legit?
616 */
617 for (unsigned i = 0; i < so->num_targets; i++) {
618 struct pipe_stream_output_target *target = so->targets[i];
619 unsigned stride = info->stride[i] * 4; /* convert dwords->bytes */
620 if (target) {
621 uint32_t max = target->buffer_size / stride;
622 maxvtxcnt = MIN2(maxvtxcnt, max);
623 }
624 }
625
626 ctx->streamout.max_tf_vtx = maxvtxcnt;
627 }
628