From 76604fd6907fdc519ffaac29168b54a2816b175f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Wed, 9 Nov 2022 19:54:09 +0100
Subject: drm/amdgpu: use the last IB as gang leader v2
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Git-commit: eca13f3c67b6ddfcc61fdb9bb1c5f9a7724e2359
Patch-mainline: v6.1-rc6
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849

It turned out that not the last IB specified is the gang leader,
but instead the last job allocated.

This is a bit unfortunate and not very intuitive for the CS
interface, so try to fix this.

Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221115094206.6181-1-christian.koenig@amd.com
Tested-by: Timur Kristóf <timur.kristof@gmail.com>
Acked-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Fixes: 4624459c84d7 ("drm/amdgpu: add gang submit frontend v6")
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 23 ++++++++++++++++-------
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h |  1 +
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index d371000a5727..de5cb056c9ad 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -109,6 +109,7 @@ static int amdgpu_cs_p1_ib(struct amdgpu_cs_parser *p,
 		return r;
 
 	++(num_ibs[r]);
+	p->gang_leader_idx = r;
 	return 0;
 }
 
@@ -300,7 +301,7 @@ static int amdgpu_cs_pass1(struct amdgpu_cs_parser *p,
 		if (ret)
 			goto free_all_kdata;
 	}
-	p->gang_leader = p->jobs[p->gang_size - 1];
+	p->gang_leader = p->jobs[p->gang_leader_idx];
 
 	if (p->ctx->vram_lost_counter != p->gang_leader->vram_lost_counter) {
 		ret = -ECANCELED;
@@ -1195,16 +1196,18 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser *p)
 			return r;
 	}
 
-	for (i = 0; i < p->gang_size - 1; ++i) {
+	for (i = 0; i < p->gang_size; ++i) {
+		if (p->jobs[i] == leader)
+			continue;
+
 		r = amdgpu_sync_clone(&leader->sync, &p->jobs[i]->sync);
 		if (r)
 			return r;
 	}
 
-	r = amdgpu_ctx_wait_prev_fence(p->ctx, p->entities[p->gang_size - 1]);
+	r = amdgpu_ctx_wait_prev_fence(p->ctx, p->entities[p->gang_leader_idx]);
 	if (r && r != -ERESTARTSYS)
 		DRM_ERROR("amdgpu_ctx_wait_prev_fence failed.\n");
-
 	return r;
 }
 
@@ -1238,9 +1241,12 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 	for (i = 0; i < p->gang_size; ++i)
 		drm_sched_job_arm(&p->jobs[i]->base);
 
-	for (i = 0; i < (p->gang_size - 1); ++i) {
+	for (i = 0; i < p->gang_size; ++i) {
 		struct dma_fence *fence;
 
+		if (p->jobs[i] == leader)
+			continue;
+
 		fence = &p->jobs[i]->base.s_fence->scheduled;
 		r = amdgpu_sync_fence(&leader->sync, fence);
 		if (r)
@@ -1276,7 +1282,10 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 	list_for_each_entry(e, &p->validated, tv.head) {
 
 		/* Everybody except for the gang leader uses READ */
-		for (i = 0; i < (p->gang_size - 1); ++i) {
+		for (i = 0; i < p->gang_size; ++i) {
+			if (p->jobs[i] == leader)
+				continue;
+
 			dma_resv_add_fence(e->tv.bo->base.resv,
 					   &p->jobs[i]->base.s_fence->finished,
 					   DMA_RESV_USAGE_READ);
@@ -1286,7 +1295,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 		e->tv.num_shared = 0;
 	}
 
-	seq = amdgpu_ctx_add_fence(p->ctx, p->entities[p->gang_size - 1],
+	seq = amdgpu_ctx_add_fence(p->ctx, p->entities[p->gang_leader_idx],
 				   p->fence);
 	amdgpu_cs_post_dependencies(p);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h
index cbaa19b2b8a3..f80adf9069ec 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h
@@ -54,6 +54,7 @@ struct amdgpu_cs_parser {
 
 	/* scheduler job objects */
 	unsigned int		gang_size;
+	unsigned int		gang_leader_idx;
 	struct drm_sched_entity	*entities[AMDGPU_CS_GANG_SIZE];
 	struct amdgpu_job	*jobs[AMDGPU_CS_GANG_SIZE];
 	struct amdgpu_job	*gang_leader;
-- 
2.38.1