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->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          BEGIN_BATCH(3);
  69          OUT_BATCH(MI_LOAD_REGISTER_IMM | (3 - 2));
  70          OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
  71          OUT_BATCH(0);
  72          ADVANCE_BATCH();
  73       }
  74    }
  75
  76    brw_obj->primitive_mode = mode;
  77 }
  78
  79 void
  80 gen7_end_transform_feedback(struct gl_context *ctx,
  81                             struct gl_transform_feedback_object *obj)
  82 {
  83    /* After EndTransformFeedback, it's likely that the client program will try
  84     * to draw using the contents of the transform feedback buffer as vertex
  85     * input.  In order for this to work, we need to flush the data through at
  86     * least the GS stage of the pipeline, and flush out the render cache.  For
  87     * simplicity, just do a full flush.
  88     */
  89    struct brw_context *brw = brw_context(ctx);
  90    struct brw_transform_feedback_object *brw_obj =
  91       (struct brw_transform_feedback_object *) obj;
  92
  93    /* Store the ending value of the SO_NUM_PRIMS_WRITTEN counters. */
  94    if (!obj->Paused)
  95       brw_save_primitives_written_counters(brw, brw_obj);
  96
  97    /* EndTransformFeedback() means that we need to update the number of
  98     * vertices written.  Since it's only necessary if DrawTransformFeedback()
  99     * is called and it means mapping a buffer object, we delay computing it
 100     * until it's absolutely necessary to try and avoid stalls.
 101     */
 102    brw_obj->vertices_written_valid = false;
 103 }
 104
 105 void
 106 gen7_pause_transform_feedback(struct gl_context *ctx,
 107                               struct gl_transform_feedback_object *obj)
 108 {
 109    struct brw_context *brw = brw_context(ctx);
 110    struct brw_transform_feedback_object *brw_obj =
 111       (struct brw_transform_feedback_object *) obj;
 112
 113    /* Flush any drawing so that the counters have the right values. */
 114    brw_emit_mi_flush(brw);
 115
 116    assert(brw->gen == 7);
 117
 118    /* Save the SOL buffer offset register values. */
 119    for (int i = 0; i < 4; i++) {
 120       BEGIN_BATCH(3);
 121       OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
 122       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 123       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 124       ADVANCE_BATCH();
 125    }
 126
 127    /* Store the temporary ending value of the SO_NUM_PRIMS_WRITTEN counters.
 128     * While this operation is paused, other transform feedback actions may
 129     * occur, which will contribute to the counters.  We need to exclude that
 130     * from our counts.
 131     */
 132    brw_save_primitives_written_counters(brw, brw_obj);
 133 }
 134
 135 void
 136 gen7_resume_transform_feedback(struct gl_context *ctx,
 137                                struct gl_transform_feedback_object *obj)
 138 {
 139    struct brw_context *brw = brw_context(ctx);
 140    struct brw_transform_feedback_object *brw_obj =
 141       (struct brw_transform_feedback_object *) obj;
 142
 143    assert(brw->gen == 7);
 144
 145    /* Reload the SOL buffer offset registers. */
 146    for (int i = 0; i < 4; i++) {
 147       BEGIN_BATCH(3);
 148       OUT_BATCH(GEN7_MI_LOAD_REGISTER_MEM | (3 - 2));
 149       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 150       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 151       ADVANCE_BATCH();
 152    }
 153
 154    /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
 155    brw_save_primitives_written_counters(brw, brw_obj);
 156 }