From 15a4b0740abcc1e34bfd158cbe836402b7bbea88 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Fri, 7 Oct 2022 09:51:13 +0200
Subject: drm/sched: add DRM_SCHED_FENCE_DONT_PIPELINE flag
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Git-commit: 7b476affcccfc7e644541a0a719f53fc7bd34c53
Patch-mainline: v6.1-rc2
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
Setting this flag on a scheduler fence prevents pipelining of jobs
depending on this fence. In other words we always insert a full CPU
round trip before dependent jobs are pushed to the pipeline.
Signed-off-by: Christian König <christian.koenig@amd.com>
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2113#note_1579296
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Luben Tuikov <luben.tuikov@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221014081553.114899-1-christian.koenig@amd.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/scheduler/sched_entity.c | 3 ++-
include/drm/gpu_scheduler.h | 9 +++++++++
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 6b25b2f4f5a3..6137537aaea4 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -385,7 +385,8 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
}
s_fence = to_drm_sched_fence(fence);
- if (s_fence && s_fence->sched == sched) {
+ if (s_fence && s_fence->sched == sched &&
+ !test_bit(DRM_SCHED_FENCE_DONT_PIPELINE, &fence->flags)) {
/*
* Fence is from the same scheduler, only need to wait for
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index addb135eeea6..289a33e80639 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -32,6 +32,15 @@
#define MAX_WAIT_SCHED_ENTITY_Q_EMPTY msecs_to_jiffies(1000)
+/**
+ * DRM_SCHED_FENCE_DONT_PIPELINE - Prefent dependency pipelining
+ *
+ * Setting this flag on a scheduler fence prevents pipelining of jobs depending
+ * on this fence. In other words we always insert a full CPU round trip before
+ * dependen jobs are pushed to the hw queue.
+ */
+#define DRM_SCHED_FENCE_DONT_PIPELINE DMA_FENCE_FLAG_USER_BITS
+
struct drm_gem_object;
struct drm_gpu_scheduler;
--
2.38.1