1 /*
2 * Copyright © 2009 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 * Authors:
24 * Eric Anholt <eric@anholt.net>
25 *
26 */
27
28 #include "main/macros.h"
29 #include "intel_batchbuffer.h"
30 #include "brw_context.h"
31 #include "brw_state.h"
32 #include "brw_defines.h"
33
34 /**
35 * When the GS is not in use, we assign the entire URB space to the VS. When
36 * the GS is in use, we split the URB space evenly between the VS and the GS.
37 * This is not ideal, but it's simple.
38 *
39 * URB size / 2 URB size / 2
40 * _____________-______________ _____________-______________
41 * / \ / \
42 * +-------------------------------------------------------------+
43 * | Vertex Shader Entries | Geometry Shader Entries |
44 * +-------------------------------------------------------------+
45 *
46 * Sandybridge GT1 has 32kB of URB space, while GT2 has 64kB.
47 * (See the Sandybridge PRM, Volume 2, Part 1, Section 1.4.7: 3DSTATE_URB.)
48 */
49 static void
gen6_upload_urb(struct brw_context * brw)50 gen6_upload_urb( struct brw_context *brw )
51 {
52 struct intel_context *intel = &brw->intel;
53 int nr_vs_entries, nr_gs_entries;
54 int total_urb_size = brw->urb.size * 1024; /* in bytes */
55
56 /* CACHE_NEW_VS_PROG */
57 brw->urb.vs_size = MAX2(brw->vs.prog_data->urb_entry_size, 1);
58
59 /* We use the same VUE layout for VS outputs and GS outputs (as it's what
60 * the SF and Clipper expect), so we can simply make the GS URB entry size
61 * the same as for the VS. This may technically be too large in cases
62 * where we have few vertex attributes and a lot of varyings, since the VS
63 * size is determined by the larger of the two. For now, it's safe.
64 */
65 brw->urb.gs_size = brw->urb.vs_size;
66
67 /* Calculate how many entries fit in each stage's section of the URB */
68 if (brw->gs.prog_active) {
69 nr_vs_entries = (total_urb_size/2) / (brw->urb.vs_size * 128);
70 nr_gs_entries = (total_urb_size/2) / (brw->urb.gs_size * 128);
71 } else {
72 nr_vs_entries = total_urb_size / (brw->urb.vs_size * 128);
73 nr_gs_entries = 0;
74 }
75
76 /* Then clamp to the maximum allowed by the hardware */
77 if (nr_vs_entries > brw->urb.max_vs_entries)
78 nr_vs_entries = brw->urb.max_vs_entries;
79
80 if (nr_gs_entries > brw->urb.max_gs_entries)
81 nr_gs_entries = brw->urb.max_gs_entries;
82
83 /* Finally, both must be a multiple of 4 (see 3DSTATE_URB in the PRM). */
84 brw->urb.nr_vs_entries = ROUND_DOWN_TO(nr_vs_entries, 4);
85 brw->urb.nr_gs_entries = ROUND_DOWN_TO(nr_gs_entries, 4);
86
87 assert(brw->urb.nr_vs_entries >= 24);
88 assert(brw->urb.nr_vs_entries % 4 == 0);
89 assert(brw->urb.nr_gs_entries % 4 == 0);
90 assert(brw->urb.vs_size < 5);
91 assert(brw->urb.gs_size < 5);
92
93 BEGIN_BATCH(3);
94 OUT_BATCH(_3DSTATE_URB << 16 | (3 - 2));
95 OUT_BATCH(((brw->urb.vs_size - 1) << GEN6_URB_VS_SIZE_SHIFT) |
96 ((brw->urb.nr_vs_entries) << GEN6_URB_VS_ENTRIES_SHIFT));
97 OUT_BATCH(((brw->urb.gs_size - 1) << GEN6_URB_GS_SIZE_SHIFT) |
98 ((brw->urb.nr_gs_entries) << GEN6_URB_GS_ENTRIES_SHIFT));
99 ADVANCE_BATCH();
100
101 /* From the PRM Volume 2 part 1, section 1.4.7:
102 *
103 * Because of a urb corruption caused by allocating a previous gsunit’s
104 * urb entry to vsunit software is required to send a "GS NULL
105 * Fence"(Send URB fence with VS URB size == 1 and GS URB size == 0) plus
106 * a dummy DRAW call before any case where VS will be taking over GS URB
107 * space.
108 *
109 * It is not clear exactly what this means ("URB fence" is a command that
110 * doesn't exist on Gen6). So for now we just do a full pipeline flush as
111 * a workaround.
112 */
113 if (brw->urb.gen6_gs_previously_active && !brw->gs.prog_active)
114 intel_batchbuffer_emit_mi_flush(intel);
115 brw->urb.gen6_gs_previously_active = brw->gs.prog_active;
116 }
117
118 const struct brw_tracked_state gen6_urb = {
119 .dirty = {
120 .mesa = 0,
121 .brw = BRW_NEW_CONTEXT,
122 .cache = (CACHE_NEW_VS_PROG | CACHE_NEW_GS_PROG),
123 },
124 .emit = gen6_upload_urb,
125 };
126