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    const struct gen_device_info *devinfo = &brw->screen->devinfo;
  46
  47    assert(devinfo->gen == 7);
  48
  49    /* We're about to lose the information needed to compute the number of
  50     * vertices written during the last Begin/EndTransformFeedback section,
  51     * so we can't delay it any further.
  52     */
  53    brw_compute_xfb_vertices_written(brw, brw_obj);
  54
  55    /* No primitives have been generated yet. */
  56    for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
  57       brw_obj->prims_generated[i] = 0;
  58    }
  59
  60    /* Store the starting value of the SO_NUM_PRIMS_WRITTEN counters. */
  61    brw_save_primitives_written_counters(brw, brw_obj);
  62
  63    /* Reset the SO buffer offsets to 0. */
  64    if (!can_do_pipelined_register_writes(brw->screen)) {
  65       intel_batchbuffer_flush(brw);
  66       brw->batch.needs_sol_reset = true;
  67    } else {
  68       for (int i = 0; i < 4; i++) {
  69          BEGIN_BATCH(3);
  70          OUT_BATCH(MI_LOAD_REGISTER_IMM | (3 - 2));
  71          OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
  72          OUT_BATCH(0);
  73          ADVANCE_BATCH();
  74       }
  75    }
  76
  77    brw_obj->primitive_mode = mode;
  78 }
  79
  80 void
  81 gen7_end_transform_feedback(struct gl_context *ctx,
  82                             struct gl_transform_feedback_object *obj)
  83 {
  84    /* After EndTransformFeedback, it's likely that the client program will try
  85     * to draw using the contents of the transform feedback buffer as vertex
  86     * input.  In order for this to work, we need to flush the data through at
  87     * least the GS stage of the pipeline, and flush out the render cache.  For
  88     * simplicity, just do a full flush.
  89     */
  90    struct brw_context *brw = brw_context(ctx);
  91    struct brw_transform_feedback_object *brw_obj =
  92       (struct brw_transform_feedback_object *) obj;
  93
  94    /* Store the ending value of the SO_NUM_PRIMS_WRITTEN counters. */
  95    if (!obj->Paused)
  96       brw_save_primitives_written_counters(brw, brw_obj);
  97
  98    /* EndTransformFeedback() means that we need to update the number of
  99     * vertices written.  Since it's only necessary if DrawTransformFeedback()
 100     * is called and it means mapping a buffer object, we delay computing it
 101     * until it's absolutely necessary to try and avoid stalls.
 102     */
 103    brw_obj->vertices_written_valid = false;
 104 }
 105
 106 void
 107 gen7_pause_transform_feedback(struct gl_context *ctx,
 108                               struct gl_transform_feedback_object *obj)
 109 {
 110    struct brw_context *brw = brw_context(ctx);
 111    struct brw_transform_feedback_object *brw_obj =
 112       (struct brw_transform_feedback_object *) obj;
 113    const struct gen_device_info *devinfo = &brw->screen->devinfo;
 114
 115    /* Flush any drawing so that the counters have the right values. */
 116    brw_emit_mi_flush(brw);
 117
 118    assert(devinfo->gen == 7);
 119
 120    /* Save the SOL buffer offset register values. */
 121    for (int i = 0; i < 4; i++) {
 122       BEGIN_BATCH(3);
 123       OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
 124       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 125       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 126       ADVANCE_BATCH();
 127    }
 128
 129    /* Store the temporary ending value of the SO_NUM_PRIMS_WRITTEN counters.
 130     * While this operation is paused, other transform feedback actions may
 131     * occur, which will contribute to the counters.  We need to exclude that
 132     * from our counts.
 133     */
 134    brw_save_primitives_written_counters(brw, brw_obj);
 135 }
 136
 137 void
 138 gen7_resume_transform_feedback(struct gl_context *ctx,
 139                                struct gl_transform_feedback_object *obj)
 140 {
 141    struct brw_context *brw = brw_context(ctx);
 142    struct brw_transform_feedback_object *brw_obj =
 143       (struct brw_transform_feedback_object *) obj;
 144    const struct gen_device_info *devinfo = &brw->screen->devinfo;
 145
 146    assert(devinfo->gen == 7);
 147
 148    /* Reload the SOL buffer offset registers. */
 149    for (int i = 0; i < 4; i++) {
 150       BEGIN_BATCH(3);
 151       OUT_BATCH(GEN7_MI_LOAD_REGISTER_MEM | (3 - 2));
 152       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 153       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 154       ADVANCE_BATCH();
 155    }
 156
 157    /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
 158    brw_save_primitives_written_counters(brw, brw_obj);
 159 }