src/mesa/drivers/dri/i965/gen7_sol_state.c

   1 /*
   2  * Copyright © 2011 Intel Corporation
   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
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * @file gen7_sol_state.c
  26  *
  27  * Controls the stream output logic (SOL) stage of the gen7 hardware, which is
  28  * used to implement GL_EXT_transform_feedback.
  29  */
  30
  31 #include "brw_context.h"
  32 #include "brw_state.h"
  33 #include "brw_defines.h"
  34 #include "intel_batchbuffer.h"
  35 #include "intel_buffer_objects.h"
  36 #include "main/transformfeedback.h"
  37
  38 void
  39 gen7_begin_transform_feedback(struct gl_context *ctx, GLenum mode,
  40                               struct gl_transform_feedback_object *obj)
  41 {
  42    struct brw_context *brw = brw_context(ctx);
  43    struct brw_transform_feedback_object *brw_obj =
  44       (struct brw_transform_feedback_object *) obj;
  45
  46    assert(brw->screen->devinfo.gen == 7);
  47
  48    /* We're about to lose the information needed to compute the number of
  49     * vertices written during the last Begin/EndTransformFeedback section,
  50     * so we can't delay it any further.
  51     */
  52    brw_compute_xfb_vertices_written(brw, brw_obj);
  53
  54    /* No primitives have been generated yet. */
  55    for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
  56       brw_obj->prims_generated[i] = 0;
  57    }
  58
  59    /* Store the starting value of the SO_NUM_PRIMS_WRITTEN counters. */
  60    brw_save_primitives_written_counters(brw, brw_obj);
  61
  62    /* Reset the SO buffer offsets to 0. */
  63    if (!can_do_pipelined_register_writes(brw->screen)) {
  64       intel_batchbuffer_flush(brw);
  65       brw->batch.needs_sol_reset = true;
  66    } else {
  67       for (int i = 0; i < 4; i++) {
  68          brw_load_register_imm32(brw, GEN7_SO_WRITE_OFFSET(i), 0);
  69       }
  70    }
  71
  72    brw_obj->primitive_mode = mode;
  73 }
  74
  75 void
  76 gen7_end_transform_feedback(struct gl_context *ctx,
  77                             struct gl_transform_feedback_object *obj)
  78 {
  79    /* After EndTransformFeedback, it's likely that the client program will try
  80     * to draw using the contents of the transform feedback buffer as vertex
  81     * input.  In order for this to work, we need to flush the data through at
  82     * least the GS stage of the pipeline, and flush out the render cache.  For
  83     * simplicity, just do a full flush.
  84     */
  85    struct brw_context *brw = brw_context(ctx);
  86    struct brw_transform_feedback_object *brw_obj =
  87       (struct brw_transform_feedback_object *) obj;
  88
  89    /* Store the ending value of the SO_NUM_PRIMS_WRITTEN counters. */
  90    if (!obj->Paused)
  91       brw_save_primitives_written_counters(brw, brw_obj);
  92
  93    /* EndTransformFeedback() means that we need to update the number of
  94     * vertices written.  Since it's only necessary if DrawTransformFeedback()
  95     * is called and it means mapping a buffer object, we delay computing it
  96     * until it's absolutely necessary to try and avoid stalls.
  97     */
  98    brw_obj->vertices_written_valid = false;
  99 }
 100
 101 void
 102 gen7_pause_transform_feedback(struct gl_context *ctx,
 103                               struct gl_transform_feedback_object *obj)
 104 {
 105    struct brw_context *brw = brw_context(ctx);
 106    struct brw_transform_feedback_object *brw_obj =
 107       (struct brw_transform_feedback_object *) obj;
 108
 109    /* Flush any drawing so that the counters have the right values. */
 110    brw_emit_mi_flush(brw);
 111
 112    assert(brw->screen->devinfo.gen == 7);
 113
 114    /* Save the SOL buffer offset register values. */
 115    for (int i = 0; i < 4; i++) {
 116       BEGIN_BATCH(3);
 117       OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
 118       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 119       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 120       ADVANCE_BATCH();
 121    }
 122
 123    /* Store the temporary ending value of the SO_NUM_PRIMS_WRITTEN counters.
 124     * While this operation is paused, other transform feedback actions may
 125     * occur, which will contribute to the counters.  We need to exclude that
 126     * from our counts.
 127     */
 128    brw_save_primitives_written_counters(brw, brw_obj);
 129 }
 130
 131 void
 132 gen7_resume_transform_feedback(struct gl_context *ctx,
 133                                struct gl_transform_feedback_object *obj)
 134 {
 135    struct brw_context *brw = brw_context(ctx);
 136    struct brw_transform_feedback_object *brw_obj =
 137       (struct brw_transform_feedback_object *) obj;
 138
 139    assert(brw->screen->devinfo.gen == 7);
 140
 141    /* Reload the SOL buffer offset registers. */
 142    for (int i = 0; i < 4; i++) {
 143       BEGIN_BATCH(3);
 144       OUT_BATCH(GEN7_MI_LOAD_REGISTER_MEM | (3 - 2));
 145       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 146       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 147       ADVANCE_BATCH();
 148    }
 149
 150    /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
 151    brw_save_primitives_written_counters(brw, brw_obj);
 152 }