From: jsg <jsg@openbsd.org>
Date: Mon, 19 Jul 2021 10:08:03 +0000 (+0000)
Subject: drm/amdgpu: remove unsafe optimization to drop preamble ib
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=59a6f105fef37c7573a1df76bef1f12bb8cafe3e;p=openbsd

drm/amdgpu: remove unsafe optimization to drop preamble ib

From Jiansong Chen
8fa6473a61ecc9972ad543d8ba1d927d442d1f67 in linux 5.10.y/5.10.51
7d9c70d23550eb86a1bec1954ccaa8d6ec3a3328 in mainline linux
---

diff --git a/sys/dev/pci/drm/amd/amdgpu/amdgpu_ib.c b/sys/dev/pci/drm/amd/amdgpu/amdgpu_ib.c
index 28f20f0b722..163188ce02b 100644
--- a/sys/dev/pci/drm/amd/amdgpu/amdgpu_ib.c
+++ b/sys/dev/pci/drm/amd/amdgpu/amdgpu_ib.c
@@ -128,7 +128,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 	struct amdgpu_device *adev = ring->adev;
 	struct amdgpu_ib *ib = &ibs[0];
 	struct dma_fence *tmp = NULL;
-	bool skip_preamble, need_ctx_switch;
+	bool need_ctx_switch;
 	unsigned patch_offset = ~0;
 	struct amdgpu_vm *vm;
 	uint64_t fence_ctx;
@@ -221,7 +221,6 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 	if (need_ctx_switch)
 		status |= AMDGPU_HAVE_CTX_SWITCH;
 
-	skip_preamble = ring->current_ctx == fence_ctx;
 	if (job && ring->funcs->emit_cntxcntl) {
 		status |= job->preamble_status;
 		status |= job->preemption_status;
@@ -239,14 +238,6 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 	for (i = 0; i < num_ibs; ++i) {
 		ib = &ibs[i];
 
-		/* drop preamble IBs if we don't have a context switch */
-		if ((ib->flags & AMDGPU_IB_FLAG_PREAMBLE) &&
-		    skip_preamble &&
-		    !(status & AMDGPU_PREAMBLE_IB_PRESENT_FIRST) &&
-		    !amdgpu_mcbp &&
-		    !amdgpu_sriov_vf(adev)) /* for SRIOV preemption, Preamble CE ib must be inserted anyway */
-			continue;
-
 		if (job && ring->funcs->emit_frame_cntl) {
 			if (secure != !!(ib->flags & AMDGPU_IB_FLAGS_SECURE)) {
 				amdgpu_ring_emit_frame_cntl(ring, false, secure);