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    /* Store the starting value of the SO_NUM_PRIMS_WRITTEN counters. */
  49    brw_save_primitives_written_counters(brw, brw_obj);
  50
  51    /* Reset the SO buffer offsets to 0. */
  52    if (!can_do_pipelined_register_writes(brw->screen)) {
  53       intel_batchbuffer_flush(brw);
  54       brw->batch.needs_sol_reset = true;
  55    } else {
  56       for (int i = 0; i < 4; i++) {
  57          brw_load_register_imm32(brw, GEN7_SO_WRITE_OFFSET(i), 0);
  58       }
  59    }
  60
  61    brw_obj->primitive_mode = mode;
  62 }
  63
  64 void
  65 gen7_end_transform_feedback(struct gl_context *ctx,
  66                             struct gl_transform_feedback_object *obj)
  67 {
  68    /* After EndTransformFeedback, it's likely that the client program will try
  69     * to draw using the contents of the transform feedback buffer as vertex
  70     * input.  In order for this to work, we need to flush the data through at
  71     * least the GS stage of the pipeline, and flush out the render cache.  For
  72     * simplicity, just do a full flush.
  73     */
  74    struct brw_context *brw = brw_context(ctx);
  75    struct brw_transform_feedback_object *brw_obj =
  76       (struct brw_transform_feedback_object *) obj;
  77
  78    /* Store the ending value of the SO_NUM_PRIMS_WRITTEN counters. */
  79    if (!obj->Paused)
  80       brw_save_primitives_written_counters(brw, brw_obj);
  81
  82    /* We've reached the end of a transform feedback begin/end block.  This
  83     * means that future DrawTransformFeedback() calls will need to pick up the
  84     * results of the current counter, and that it's time to roll back the
  85     * current primitive counter to zero.
  86     */
  87    brw_obj->previous_counter = brw_obj->counter;
  88    brw_reset_transform_feedback_counter(&brw_obj->counter);
  89
  90    /* EndTransformFeedback() means that we need to update the number of
  91     * vertices written.  Since it's only necessary if DrawTransformFeedback()
  92     * is called and it means mapping a buffer object, we delay computing it
  93     * until it's absolutely necessary to try and avoid stalls.
  94     */
  95    brw_obj->vertices_written_valid = false;
  96 }
  97
  98 void
  99 gen7_pause_transform_feedback(struct gl_context *ctx,
 100                               struct gl_transform_feedback_object *obj)
 101 {
 102    struct brw_context *brw = brw_context(ctx);
 103    struct brw_transform_feedback_object *brw_obj =
 104       (struct brw_transform_feedback_object *) obj;
 105
 106    /* Flush any drawing so that the counters have the right values. */
 107    brw_emit_mi_flush(brw);
 108
 109    assert(brw->screen->devinfo.gen == 7);
 110
 111    /* Save the SOL buffer offset register values. */
 112    for (int i = 0; i < 4; i++) {
 113       BEGIN_BATCH(3);
 114       OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
 115       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 116       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 117       ADVANCE_BATCH();
 118    }
 119
 120    /* Store the temporary ending value of the SO_NUM_PRIMS_WRITTEN counters.
 121     * While this operation is paused, other transform feedback actions may
 122     * occur, which will contribute to the counters.  We need to exclude that
 123     * from our counts.
 124     */
 125    brw_save_primitives_written_counters(brw, brw_obj);
 126 }
 127
 128 void
 129 gen7_resume_transform_feedback(struct gl_context *ctx,
 130                                struct gl_transform_feedback_object *obj)
 131 {
 132    struct brw_context *brw = brw_context(ctx);
 133    struct brw_transform_feedback_object *brw_obj =
 134       (struct brw_transform_feedback_object *) obj;
 135
 136    assert(brw->screen->devinfo.gen == 7);
 137
 138    /* Reload the SOL buffer offset registers. */
 139    for (int i = 0; i < 4; i++) {
 140       BEGIN_BATCH(3);
 141       OUT_BATCH(GEN7_MI_LOAD_REGISTER_MEM | (3 - 2));
 142       OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
 143       OUT_RELOC(brw_obj->offset_bo, RELOC_WRITE, i * sizeof(uint32_t));
 144       ADVANCE_BATCH();
 145    }
 146
 147    /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
 148    brw_save_primitives_written_counters(brw, brw_obj);
 149 }