On 8/20/2021 15:44, Matthew Brost wrote:
Implement multi-lrc submission via a single workqueue entry and single
H2G. The workqueue entry contains an updated tail value for each
request, of all the contexts in the multi-lrc submission, and updates
these values simultaneously. As such, the tasklet and bypass path have
been updated to coalesce requests into a single submission.
Signed-off-by: Matthew Brost <matthew.br...@intel.com>
---
drivers/gpu/drm/i915/gt/uc/intel_guc.c | 21 ++
drivers/gpu/drm/i915/gt/uc/intel_guc.h | 8 +
drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 24 +-
drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 6 +-
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 312 +++++++++++++++---
drivers/gpu/drm/i915/i915_request.h | 8 +
6 files changed, 317 insertions(+), 62 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.c
b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
index fbfcae727d7f..879aef662b2e 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
@@ -748,3 +748,24 @@ void intel_guc_load_status(struct intel_guc *guc, struct
drm_printer *p)
}
}
}
+
+void intel_guc_write_barrier(struct intel_guc *guc)
+{
+ struct intel_gt *gt = guc_to_gt(guc);
+
+ if (i915_gem_object_is_lmem(guc->ct.vma->obj)) {
+ GEM_BUG_ON(guc->send_regs.fw_domains);
Granted, this patch is just moving code from one file to another not
changing it. However, I think it would be worth adding a blank line in
here. Otherwise the 'this register' comment below can be confusingly
read as referring to the send_regs.fw_domain entry above.
And maybe add a comment why it is a bug for the send_regs value to be
set? I'm not seeing any obvious connection between it and the reset of
this code.
+ /*
+ * This register is used by the i915 and GuC for MMIO based
+ * communication. Once we are in this code CTBs are the only
+ * method the i915 uses to communicate with the GuC so it is
+ * safe to write to this register (a value of 0 is NOP for MMIO
+ * communication). If we ever start mixing CTBs and MMIOs a new
+ * register will have to be chosen.
+ */
+ intel_uncore_write_fw(gt->uncore, GEN11_SOFT_SCRATCH(0), 0);
+ } else {
+ /* wmb() sufficient for a barrier if in smem */
+ wmb();
+ }
+}
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 3f95b1b4f15c..0ead2406d03c 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -37,6 +37,12 @@ struct intel_guc {
/* Global engine used to submit requests to GuC */
struct i915_sched_engine *sched_engine;
struct i915_request *stalled_request;
+ enum {
+ STALL_NONE,
+ STALL_REGISTER_CONTEXT,
+ STALL_MOVE_LRC_TAIL,
+ STALL_ADD_REQUEST,
+ } submission_stall_reason;
/* intel_guc_recv interrupt related state */
spinlock_t irq_lock;
@@ -332,4 +338,6 @@ void intel_guc_submission_cancel_requests(struct intel_guc
*guc);
void intel_guc_load_status(struct intel_guc *guc, struct drm_printer *p);
+void intel_guc_write_barrier(struct intel_guc *guc);
+
#endif
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
index 20c710a74498..10d1878d2826 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
@@ -377,28 +377,6 @@ static u32 ct_get_next_fence(struct intel_guc_ct *ct)
return ++ct->requests.last_fence;
}
-static void write_barrier(struct intel_guc_ct *ct)
-{
- struct intel_guc *guc = ct_to_guc(ct);
- struct intel_gt *gt = guc_to_gt(guc);
-
- if (i915_gem_object_is_lmem(guc->ct.vma->obj)) {
- GEM_BUG_ON(guc->send_regs.fw_domains);
- /*
- * This register is used by the i915 and GuC for MMIO based
- * communication. Once we are in this code CTBs are the only
- * method the i915 uses to communicate with the GuC so it is
- * safe to write to this register (a value of 0 is NOP for MMIO
- * communication). If we ever start mixing CTBs and MMIOs a new
- * register will have to be chosen.
- */
- intel_uncore_write_fw(gt->uncore, GEN11_SOFT_SCRATCH(0), 0);
- } else {
- /* wmb() sufficient for a barrier if in smem */
- wmb();
- }
-}
-
static int ct_write(struct intel_guc_ct *ct,
const u32 *action,
u32 len /* in dwords */,
@@ -468,7 +446,7 @@ static int ct_write(struct intel_guc_ct *ct,
* make sure H2G buffer update and LRC tail update (if this triggering a
* submission) are visible before updating the descriptor tail
*/
- write_barrier(ct);
+ intel_guc_write_barrier(ct_to_guc(ct));
/* update local copies */
ctb->tail = tail;
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
index 0e600a3b8f1e..6cd26dc060d1 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
@@ -65,12 +65,14 @@
#define WQ_TYPE_PSEUDO (0x2 << WQ_TYPE_SHIFT)
#define WQ_TYPE_INORDER (0x3 << WQ_TYPE_SHIFT)
#define WQ_TYPE_NOOP (0x4 << WQ_TYPE_SHIFT)
-#define WQ_TARGET_SHIFT 10
+#define WQ_TYPE_MULTI_LRC (0x5 << WQ_TYPE_SHIFT)
+#define WQ_TARGET_SHIFT 8
#define WQ_LEN_SHIFT 16
#define WQ_NO_WCFLUSH_WAIT (1 << 27)
#define WQ_PRESENT_WORKLOAD (1 << 28)
-#define WQ_RING_TAIL_SHIFT 20
+#define WQ_GUC_ID_SHIFT 0
+#define WQ_RING_TAIL_SHIFT 18
Presumably all of these API changes are not actually new? They really
came in with the reset of the v40 re-write? It's just that this is the
first time we are using them and therefore need to finally update the
defines?
#define WQ_RING_TAIL_MAX 0x7FF /* 2^11 QWords */
#define WQ_RING_TAIL_MASK (WQ_RING_TAIL_MAX << WQ_RING_TAIL_SHIFT)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index e9dfd43d29a0..b107ad095248 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -391,6 +391,29 @@ __get_process_desc(struct intel_context *ce)
LRC_STATE_OFFSET) / sizeof(u32)));
}
+static u32 *get_wq_pointer(struct guc_process_desc *desc,
+ struct intel_context *ce,
+ u32 wqi_size)
+{
+ /*
+ * Check for space in work queue. Caching a value of head pointer in
+ * intel_context structure in order reduce the number accesses to shared
+ * GPU memory which may be across a PCIe bus.
+ */
+#define AVAILABLE_SPACE \
+ CIRC_SPACE(ce->guc_wqi_tail, ce->guc_wqi_head, GUC_WQ_SIZE)
+ if (wqi_size > AVAILABLE_SPACE) {
+ ce->guc_wqi_head = READ_ONCE(desc->head);
+
+ if (wqi_size > AVAILABLE_SPACE)
+ return NULL;
+ }
+#undef AVAILABLE_SPACE
+
+ return ((u32 *)__get_process_desc(ce)) +
+ ((WQ_OFFSET + ce->guc_wqi_tail) / sizeof(u32));
+}
+
static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index)
{
struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;
@@ -547,10 +570,10 @@ int intel_guc_wait_for_idle(struct intel_guc *guc, long
timeout)
static int guc_lrc_desc_pin(struct intel_context *ce, bool loop);
-static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
+static int __guc_add_request(struct intel_guc *guc, struct i915_request *rq)
{
int err = 0;
- struct intel_context *ce = rq->context;
+ struct intel_context *ce = request_to_scheduling_context(rq);
u32 action[3];
int len = 0;
u32 g2h_len_dw = 0;
@@ -571,26 +594,17 @@ static int guc_add_request(struct intel_guc *guc, struct
i915_request *rq)
GEM_BUG_ON(!atomic_read(&ce->guc_id.ref));
GEM_BUG_ON(context_guc_id_invalid(ce));
- /*
- * Corner case where the GuC firmware was blown away and reloaded while
- * this context was pinned.
- */
- if (unlikely(!lrc_desc_registered(guc, ce->guc_id.id))) {
- err = guc_lrc_desc_pin(ce, false);
- if (unlikely(err))
- return err;
- }
-
spin_lock(&ce->guc_state.lock);
/*
* The request / context will be run on the hardware when scheduling
- * gets enabled in the unblock.
+ * gets enabled in the unblock. For multi-lrc we still submit the
+ * context to move the LRC tails.
*/
- if (unlikely(context_blocked(ce)))
+ if (unlikely(context_blocked(ce) && !intel_context_is_parent(ce)))
goto out;
- enabled = context_enabled(ce);
+ enabled = context_enabled(ce) || context_blocked(ce);
Would be better to say '|| is_parent(ce)' rather than blocked? The
reason for reason for claiming enabled when not is because it's a
multi-LRC parent, right? Or can there be a parent that is neither
enabled nor blocked for which we don't want to do the processing? But
why would that make sense/be possible?
if (!enabled) {
action[len++] = INTEL_GUC_ACTION_SCHED_CONTEXT_MODE_SET;
@@ -609,6 +623,18 @@ static int guc_add_request(struct intel_guc *guc, struct
i915_request *rq)
trace_intel_context_sched_enable(ce);
atomic_inc(&guc->outstanding_submission_g2h);
set_context_enabled(ce);
+
+ /*
+ * Without multi-lrc KMD does the submission step (moving the
+ * lrc tail) so enabling scheduling is sufficient to submit the
+ * context. This isn't the case in multi-lrc submission as the
+ * GuC needs to move the tails, hence the need for another H2G
+ * to submit a multi-lrc context after enabling scheduling.
+ */
+ if (intel_context_is_parent(ce)) {
+ action[0] = INTEL_GUC_ACTION_SCHED_CONTEXT;
+ err = intel_guc_send_nb(guc, action, len - 1, 0);
+ }
} else if (!enabled) {
clr_context_pending_enable(ce);
intel_context_put(ce);
@@ -621,6 +647,18 @@ static int guc_add_request(struct intel_guc *guc, struct
i915_request *rq)
return err;
}
+static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
+{
+ int ret = __guc_add_request(guc, rq);
+
+ if (unlikely(ret == -EBUSY)) {
+ guc->stalled_request= rq;
+ guc->submission_stall_reason = STALL_ADD_REQUEST;
+ }
+
+ return ret;
+}
+
static void guc_set_lrc_tail(struct i915_request *rq)
{
rq->context->lrc_reg_state[CTX_RING_TAIL] =
@@ -632,6 +670,127 @@ static int rq_prio(const struct i915_request *rq)
return rq->sched.attr.priority;
}
+static bool is_multi_lrc_rq(struct i915_request *rq)
+{
+ return intel_context_is_child(rq->context) ||
+ intel_context_is_parent(rq->context);
+}
+
+static bool can_merge_rq(struct i915_request *rq,
+ struct i915_request *last)
+{
+ return request_to_scheduling_context(rq) ==
+ request_to_scheduling_context(last);
+}
+
+static u32 wq_space_until_wrap(struct intel_context *ce)
+{
+ return (GUC_WQ_SIZE - ce->guc_wqi_tail);
+}
+
+static void write_wqi(struct guc_process_desc *desc,
+ struct intel_context *ce,
+ u32 wqi_size)
+{
+ /*
+ * Ensure WQE are visible before updating tail
WQE or WQI?
+ */
+ intel_guc_write_barrier(ce_to_guc(ce));
+
+ ce->guc_wqi_tail = (ce->guc_wqi_tail + wqi_size) & (GUC_WQ_SIZE - 1);
+ WRITE_ONCE(desc->tail, ce->guc_wqi_tail);
+}
+
+static int guc_wq_noop_append(struct intel_context *ce)
+{
+ struct guc_process_desc *desc = __get_process_desc(ce);
+ u32 *wqi = get_wq_pointer(desc, ce, wq_space_until_wrap(ce));
+
+ if (!wqi)
+ return -EBUSY;
+
+ *wqi = WQ_TYPE_NOOP |
+ ((wq_space_until_wrap(ce) / sizeof(u32) - 1) << WQ_LEN_SHIFT);
This should have a BUG_ON check that the requested size fits within the
WQ_LEN field?
Indeed, would be better to use the FIELD macros as they do that kind of
thing for you.
+ ce->guc_wqi_tail = 0;
+
+ return 0;
+}
+
+static int __guc_wq_item_append(struct i915_request *rq)
+{
+ struct intel_context *ce = request_to_scheduling_context(rq);
+ struct intel_context *child;
+ struct guc_process_desc *desc = __get_process_desc(ce);
+ unsigned int wqi_size = (ce->guc_number_children + 4) *
+ sizeof(u32);
+ u32 *wqi;
+ int ret;
+
+ /* Ensure context is in correct state updating work queue */
+ GEM_BUG_ON(!atomic_read(&ce->guc_id.ref));
+ GEM_BUG_ON(context_guc_id_invalid(ce));
+ GEM_BUG_ON(context_wait_for_deregister_to_register(ce));
+ GEM_BUG_ON(!lrc_desc_registered(ce_to_guc(ce), ce->guc_id.id));
+
+ /* Insert NOOP if this work queue item will wrap the tail pointer. */
+ if (wqi_size > wq_space_until_wrap(ce)) {
+ ret = guc_wq_noop_append(ce);
+ if (ret)
+ return ret;
+ }
+
+ wqi = get_wq_pointer(desc, ce, wqi_size);
+ if (!wqi)
+ return -EBUSY;
+
+ *wqi++ = WQ_TYPE_MULTI_LRC |
+ ((wqi_size / sizeof(u32) - 1) << WQ_LEN_SHIFT);
+ *wqi++ = ce->lrc.lrca;
+ *wqi++ = (ce->guc_id.id << WQ_GUC_ID_SHIFT) |
+ ((ce->ring->tail / sizeof(u64)) << WQ_RING_TAIL_SHIFT);
As above, would be better to use FIELD macros instead of manual shifting.
John.
+ *wqi++ = 0; /* fence_id */
+ for_each_child(ce, child)
+ *wqi++ = child->ring->tail / sizeof(u64);
+
+ write_wqi(desc, ce, wqi_size);
+
+ return 0;
+}
+
+static int guc_wq_item_append(struct intel_guc *guc,
+ struct i915_request *rq)
+{
+ struct intel_context *ce = request_to_scheduling_context(rq);
+ int ret = 0;
+
+ if (likely(!intel_context_is_banned(ce))) {
+ ret = __guc_wq_item_append(rq);
+
+ if (unlikely(ret == -EBUSY)) {
+ guc->stalled_request = rq;
+ guc->submission_stall_reason = STALL_MOVE_LRC_TAIL;
+ }
+ }
+
+ return ret;
+}
+
+static bool multi_lrc_submit(struct i915_request *rq)
+{
+ struct intel_context *ce = request_to_scheduling_context(rq);
+
+ intel_ring_set_tail(rq->ring, rq->tail);
+
+ /*
+ * We expect the front end (execbuf IOCTL) to set this flag on the last
+ * request generated from a multi-BB submission. This indicates to the
+ * backend (GuC interface) that we should submit this context thus
+ * submitting all the requests generated in parallel.
+ */
+ return test_bit(I915_FENCE_FLAG_SUBMIT_PARALLEL, &rq->fence.flags) ||
+ intel_context_is_banned(ce);
+}
+
static int guc_dequeue_one_context(struct intel_guc *guc)
{
struct i915_sched_engine * const sched_engine = guc->sched_engine;
@@ -645,7 +804,17 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
if (guc->stalled_request) {
submit = true;
last = guc->stalled_request;
- goto resubmit;
+
+ switch (guc->submission_stall_reason) {
+ case STALL_REGISTER_CONTEXT:
+ goto register_context;
+ case STALL_MOVE_LRC_TAIL:
+ goto move_lrc_tail;
+ case STALL_ADD_REQUEST:
+ goto add_request;
+ default:
+ MISSING_CASE(guc->submission_stall_reason);
+ }
}
while ((rb = rb_first_cached(&sched_engine->queue))) {
@@ -653,8 +822,8 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
struct i915_request *rq, *rn;
priolist_for_each_request_consume(rq, rn, p) {
- if (last && rq->context != last->context)
- goto done;
+ if (last && !can_merge_rq(rq, last))
+ goto register_context;
list_del_init(&rq->sched.link);
@@ -662,33 +831,84 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
trace_i915_request_in(rq, 0);
last = rq;
- submit = true;
+
+ if (is_multi_lrc_rq(rq)) {
+ /*
+ * We need to coalesce all multi-lrc requests in
+ * a relationship into a single H2G. We are
+ * guaranteed that all of these requests will be
+ * submitted sequentially.
+ */
+ if (multi_lrc_submit(rq)) {
+ submit = true;
+ goto register_context;
+ }
+ } else {
+ submit = true;
+ }
}
rb_erase_cached(&p->node, &sched_engine->queue);
i915_priolist_free(p);
}
-done:
+
+register_context:
if (submit) {
- guc_set_lrc_tail(last);
-resubmit:
+ struct intel_context *ce = request_to_scheduling_context(last);
+
+ if (unlikely(!lrc_desc_registered(guc, ce->guc_id.id) &&
+ !intel_context_is_banned(ce))) {
+ ret = guc_lrc_desc_pin(ce, false);
+ if (unlikely(ret == -EPIPE)) {
+ goto deadlk;
+ } else if (ret == -EBUSY) {
+ guc->stalled_request = last;
+ guc->submission_stall_reason =
+ STALL_REGISTER_CONTEXT;
+ goto schedule_tasklet;
+ } else if (ret != 0) {
+ GEM_WARN_ON(ret); /* Unexpected */
+ goto deadlk;
+ }
+ }
+
+move_lrc_tail:
+ if (is_multi_lrc_rq(last)) {
+ ret = guc_wq_item_append(guc, last);
+ if (ret == -EBUSY) {
+ goto schedule_tasklet;
+ } else if (ret != 0) {
+ GEM_WARN_ON(ret); /* Unexpected */
+ goto deadlk;
+ }
+ } else {
+ guc_set_lrc_tail(last);
+ }
+
+add_request:
ret = guc_add_request(guc, last);
- if (unlikely(ret == -EPIPE))
+ if (unlikely(ret == -EPIPE)) {
+ goto deadlk;
+ } else if (ret == -EBUSY) {
+ goto schedule_tasklet;
+ } else if (ret != 0) {
+ GEM_WARN_ON(ret); /* Unexpected */
goto deadlk;
- else if (ret == -EBUSY) {
- tasklet_schedule(&sched_engine->tasklet);
- guc->stalled_request = last;
- return false;
}
}
guc->stalled_request = NULL;
+ guc->submission_stall_reason = STALL_NONE;
return submit;
deadlk:
sched_engine->tasklet.callback = NULL;
tasklet_disable_nosync(&sched_engine->tasklet);
return false;
+
+schedule_tasklet:
+ tasklet_schedule(&sched_engine->tasklet);
+ return false;
}
static void guc_submission_tasklet(struct tasklet_struct *t)
@@ -1227,10 +1447,16 @@ static int guc_bypass_tasklet_submit(struct intel_guc
*guc,
trace_i915_request_in(rq, 0);
- guc_set_lrc_tail(rq);
- ret = guc_add_request(guc, rq);
- if (ret == -EBUSY)
- guc->stalled_request = rq;
+ if (is_multi_lrc_rq(rq)) {
+ if (multi_lrc_submit(rq)) {
+ ret = guc_wq_item_append(guc, rq);
+ if (!ret)
+ ret = guc_add_request(guc, rq);
+ }
+ } else {
+ guc_set_lrc_tail(rq);
+ ret = guc_add_request(guc, rq);
+ }
if (unlikely(ret == -EPIPE))
disable_submission(guc);
@@ -1238,6 +1464,16 @@ static int guc_bypass_tasklet_submit(struct intel_guc
*guc,
return ret;
}
+bool need_tasklet(struct intel_guc *guc, struct i915_request *rq)
+{
+ struct i915_sched_engine *sched_engine = rq->engine->sched_engine;
+ struct intel_context *ce = request_to_scheduling_context(rq);
+
+ return submission_disabled(guc) || guc->stalled_request ||
+ !i915_sched_engine_is_empty(sched_engine) ||
+ !lrc_desc_registered(guc, ce->guc_id.id);
+}
+
static void guc_submit_request(struct i915_request *rq)
{
struct i915_sched_engine *sched_engine = rq->engine->sched_engine;
@@ -1247,8 +1483,7 @@ static void guc_submit_request(struct i915_request *rq)
/* Will be called from irq-context when using foreign fences. */
spin_lock_irqsave(&sched_engine->lock, flags);
- if (submission_disabled(guc) || guc->stalled_request ||
- !i915_sched_engine_is_empty(sched_engine))
+ if (need_tasklet(guc, rq))
queue_request(sched_engine, rq, rq_prio(rq));
else if (guc_bypass_tasklet_submit(guc, rq) == -EBUSY)
tasklet_hi_schedule(&sched_engine->tasklet);
@@ -2241,9 +2476,10 @@ static bool new_guc_prio_higher(u8 old_guc_prio, u8
new_guc_prio)
static void add_to_context(struct i915_request *rq)
{
- struct intel_context *ce = rq->context;
+ struct intel_context *ce = request_to_scheduling_context(rq);
u8 new_guc_prio = map_i915_prio_to_guc_prio(rq_prio(rq));
+ GEM_BUG_ON(intel_context_is_child(ce));
GEM_BUG_ON(rq->guc_prio == GUC_PRIO_FINI);
spin_lock(&ce->guc_state.lock);
@@ -2276,7 +2512,9 @@ static void guc_prio_fini(struct i915_request *rq, struct
intel_context *ce)
static void remove_from_context(struct i915_request *rq)
{
- struct intel_context *ce = rq->context;
+ struct intel_context *ce = request_to_scheduling_context(rq);
+
+ GEM_BUG_ON(intel_context_is_child(ce));
spin_lock_irq(&ce->guc_state.lock);
@@ -2692,7 +2930,7 @@ static void guc_init_breadcrumbs(struct intel_engine_cs *engine)
static void guc_bump_inflight_request_prio(struct i915_request *rq,
int prio)
{
- struct intel_context *ce = rq->context;
+ struct intel_context *ce = request_to_scheduling_context(rq);
u8 new_guc_prio = map_i915_prio_to_guc_prio(prio);
/* Short circuit function */
@@ -2715,7 +2953,7 @@ static void guc_bump_inflight_request_prio(struct
i915_request *rq,
static void guc_retire_inflight_request_prio(struct i915_request *rq)
{
- struct intel_context *ce = rq->context;
+ struct intel_context *ce = request_to_scheduling_context(rq);
spin_lock(&ce->guc_state.lock);
guc_prio_fini(rq, ce);
diff --git a/drivers/gpu/drm/i915/i915_request.h
b/drivers/gpu/drm/i915/i915_request.h
index 177eaf55adff..8f0073e19079 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -139,6 +139,14 @@ enum {
* the GPU. Here we track such boost requests on a per-request basis.
*/
I915_FENCE_FLAG_BOOST,
+
+ /*
+ * I915_FENCE_FLAG_SUBMIT_PARALLEL - request with a context in a
+ * parent-child relationship (parallel submission, multi-lrc) should
+ * trigger a submission to the GuC rather than just moving the context
+ * tail.
+ */
+ I915_FENCE_FLAG_SUBMIT_PARALLEL,
};
/**
