Instead of tediously and fragilely counting up the number of dwords
required to emit the breadcrumb to seal a request, fake a request and
measure it automatically once during engine setup.
The downside is that this requires a fair amount of mocking to create a
proper breadcrumb. Still, should be less error prone in future as the
breadcrumb size fluctuates!
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_engine_cs.c | 49 ++++++++++++++++++++
drivers/gpu/drm/i915/intel_lrc.c | 12 +++--
drivers/gpu/drm/i915/intel_ringbuffer.c | 24 +++++++---
drivers/gpu/drm/i915/intel_ringbuffer.h | 2 +-
drivers/gpu/drm/i915/selftests/mock_engine.c | 4 +-
5 files changed, 77 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 2f3c71f6d313..883ba208d1c2 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -604,6 +604,47 @@ static void __intel_context_unpin(struct i915_gem_context *ctx,
intel_context_unpin(to_intel_context(ctx, engine));
}
+struct measure_breadcrumb {
+ struct i915_request rq;
+ struct i915_timeline timeline;
+ struct intel_ring ring;
+ u32 cs[1024];
+};
+
+static int measure_breadcrumb_sz(struct intel_engine_cs *engine)
+{
+ struct measure_breadcrumb *frame;
+ unsigned int dw;
+
+ GEM_BUG_ON(!engine->i915->gt.scratch);
+
+ frame = kzalloc(sizeof(*frame), GFP_KERNEL);
+ if (!frame)
+ return -ENOMEM;
+
+ i915_timeline_init(engine->i915, &frame->timeline, engine->name);
+
+ frame->ring.timeline = &frame->timeline;
+ frame->ring.vaddr = frame->cs;
+ frame->ring.size = sizeof(frame->cs);
+ frame->ring.effective_size = frame->ring.size;
+ frame->ring.space = frame->ring.size - 8;
+ INIT_LIST_HEAD(&frame->ring.request_list);
+
+ frame->rq.i915 = engine->i915;
+ frame->rq.engine = engine;
+ frame->rq.ring = &frame->ring;
+ frame->rq.timeline = &frame->timeline;
+
+ dw = engine->emit_breadcrumb(&frame->rq, frame->cs) - frame->cs;
+ GEM_BUG_ON(dw != engine->emit_breadcrumb_sz);
+
+ i915_timeline_fini(&frame->timeline);
+ kfree(frame);
+
+ return dw;
+}
+
/**
* intel_engines_init_common - initialize cengine state which might require hw access
* @engine: Engine to initialize.
@@ -657,8 +698,16 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
if (ret)
goto err_breadcrumbs;
+ ret = measure_breadcrumb_sz(engine);
+ if (ret < 0)
+ goto err_status_page;
+
+ engine->emit_breadcrumb_sz = ret;
+
return 0;
+err_status_page:
+ cleanup_status_page(engine);
err_breadcrumbs:
intel_engine_fini_breadcrumbs(engine);
err_unpin_preempt:
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 9155cc675924..d2299425cf2f 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2051,15 +2051,17 @@ static int gen8_emit_flush_render(struct i915_request *request,
* used as a workaround for not being allowed to do lite
* restore with HEAD==TAIL (WaIdleLiteRestore).
*/
-static void gen8_emit_wa_tail(struct i915_request *request, u32 *cs)
+static u32 *gen8_emit_wa_tail(struct i915_request *request, u32 *cs)
{
/* Ensure there's always at least one preemption point per-request. */
*cs++ = MI_ARB_CHECK;
*cs++ = MI_NOOP;
request->wa_tail = intel_ring_offset(request, cs);
+
+ return cs;
}
-static void gen8_emit_breadcrumb(struct i915_request *request, u32 *cs)
+static u32 *gen8_emit_breadcrumb(struct i915_request *request, u32 *cs)
{
/* w/a: bit 5 needs to be zero for MI_FLUSH_DW address. */
BUILD_BUG_ON(I915_GEM_HWS_INDEX_ADDR & (1 << 5));
@@ -2071,11 +2073,11 @@ static void gen8_emit_breadcrumb(struct i915_request *request, u32 *cs)
request->tail = intel_ring_offset(request, cs);
assert_ring_tail_valid(request->ring, request->tail);
- gen8_emit_wa_tail(request, cs);
+ return gen8_emit_wa_tail(request, cs);
}
static const int gen8_emit_breadcrumb_sz = 6 + WA_TAIL_DWORDS;
-static void gen8_emit_breadcrumb_rcs(struct i915_request *request, u32 *cs)
+static u32 *gen8_emit_breadcrumb_rcs(struct i915_request *request, u32 *cs)
{
/* We're using qword write, seqno should be aligned to 8 bytes. */
BUILD_BUG_ON(I915_GEM_HWS_INDEX & 1);
@@ -2095,7 +2097,7 @@ static void gen8_emit_breadcrumb_rcs(struct i915_request *request, u32 *cs)
request->tail = intel_ring_offset(request, cs);
assert_ring_tail_valid(request->ring, request->tail);
- gen8_emit_wa_tail(request, cs);
+ return gen8_emit_wa_tail(request, cs);
}
static const int gen8_emit_breadcrumb_rcs_sz = 8 + WA_TAIL_DWORDS;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index e39e483d8d16..107c4934e2fa 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -299,7 +299,7 @@ gen6_render_ring_flush(struct i915_request *rq, u32 mode)
return 0;
}
-static void gen6_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
+static u32 *gen6_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
{
/* First we do the gen6_emit_post_sync_nonzero_flush w/a */
*cs++ = GFX_OP_PIPE_CONTROL(4);
@@ -327,6 +327,8 @@ static void gen6_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
rq->tail = intel_ring_offset(rq, cs);
assert_ring_tail_valid(rq->ring, rq->tail);
+
+ return cs;
}
static const int gen6_rcs_emit_breadcrumb_sz = 14;
@@ -409,7 +411,7 @@ gen7_render_ring_flush(struct i915_request *rq, u32 mode)
return 0;
}
-static void gen7_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
+static u32 *gen7_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
{
*cs++ = GFX_OP_PIPE_CONTROL(4);
*cs++ = (PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH |
@@ -427,10 +429,12 @@ static void gen7_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
rq->tail = intel_ring_offset(rq, cs);
assert_ring_tail_valid(rq->ring, rq->tail);
+
+ return cs;
}
static const int gen7_rcs_emit_breadcrumb_sz = 6;
-static void gen6_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
+static u32 *gen6_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
{
*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW;
*cs++ = intel_hws_seqno_address(rq->engine) | MI_FLUSH_DW_USE_GTT;
@@ -439,11 +443,13 @@ static void gen6_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
rq->tail = intel_ring_offset(rq, cs);
assert_ring_tail_valid(rq->ring, rq->tail);
+
+ return cs;
}
static const int gen6_xcs_emit_breadcrumb_sz = 4;
#define GEN7_XCS_WA 32
-static void gen7_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
+static u32 *gen7_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
{
int i;
@@ -466,6 +472,8 @@ static void gen7_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
rq->tail = intel_ring_offset(rq, cs);
assert_ring_tail_valid(rq->ring, rq->tail);
+
+ return cs;
}
static const int gen7_xcs_emit_breadcrumb_sz = 8 + GEN7_XCS_WA * 3;
#undef GEN7_XCS_WA
@@ -861,7 +869,7 @@ static void i9xx_submit_request(struct i915_request *request)
intel_ring_set_tail(request->ring, request->tail));
}
-static void i9xx_emit_breadcrumb(struct i915_request *rq, u32 *cs)
+static u32 *i9xx_emit_breadcrumb(struct i915_request *rq, u32 *cs)
{
*cs++ = MI_FLUSH;
@@ -874,11 +882,13 @@ static void i9xx_emit_breadcrumb(struct i915_request *rq, u32 *cs)
rq->tail = intel_ring_offset(rq, cs);
assert_ring_tail_valid(rq->ring, rq->tail);
+
+ return cs;
}
static const int i9xx_emit_breadcrumb_sz = 6;
#define GEN5_WA_STORES 8 /* must be at least 1! */
-static void gen5_emit_breadcrumb(struct i915_request *rq, u32 *cs)
+static u32 *gen5_emit_breadcrumb(struct i915_request *rq, u32 *cs)
{
int i;
@@ -895,6 +905,8 @@ static void gen5_emit_breadcrumb(struct i915_request *rq, u32 *cs)
rq->tail = intel_ring_offset(rq, cs);
assert_ring_tail_valid(rq->ring, rq->tail);
+
+ return cs;
}
static const int gen5_emit_breadcrumb_sz = GEN5_WA_STORES * 3 + 2;
#undef GEN5_WA_STORES
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index c3ef0f9bf321..479bd53d4ac6 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -470,7 +470,7 @@ struct intel_engine_cs {
unsigned int dispatch_flags);
#define I915_DISPATCH_SECURE BIT(0)
#define I915_DISPATCH_PINNED BIT(1)
- void (*emit_breadcrumb)(struct i915_request *rq, u32 *cs);
+ u32 *(*emit_breadcrumb)(struct i915_request *rq, u32 *cs);
int emit_breadcrumb_sz;
/* Pass the request to the hardware queue (e.g. directly into
diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index 442ec2aeec81..905318b7ae18 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -159,9 +159,9 @@ static int mock_emit_flush(struct i915_request *request,
return 0;
}
-static void mock_emit_breadcrumb(struct i915_request *request,
- u32 *flags)
+static u32 *mock_emit_breadcrumb(struct i915_request *request, u32 *cs)
{
+ return cs;
}
static void mock_submit_request(struct i915_request *request)
--
2.20.1
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