linux-kernel - [PATCH AUTOSEL 5.5 235/542] drm/amdgpu: fix KIQ ring test fail in TDR of SRIOV

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Date:   Fri, 14 Feb 2020 10:43:47 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Monk Liu <Monk.Liu@....com>, Emily Deng <Emily.Deng@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.5 235/542] drm/amdgpu: fix KIQ ring test fail in TDR of SRIOV

From: Monk Liu <Monk.Liu@....com>

[ Upstream commit 5a7489a7e189ee2be889485f90c8cf24ea4b9a40 ]

issues:
MEC is ruined by the amdkfd_pre_reset after VF FLR done

fix:
amdkfd_pre_reset() would ruin MEC after hypervisor finished the VF FLR,
the correct sequence is do amdkfd_pre_reset before VF FLR but there is
a limitation to block this sequence:
if we do pre_reset() before VF FLR, it would go KIQ way to do register
access and stuck there, because KIQ probably won't work by that time
(e.g. you already made GFX hang)

so the best way right now is to simply remove it.

Signed-off-by: Monk Liu <Monk.Liu@....com>
Reviewed-by: Emily Deng <Emily.Deng@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index c17505fba9884..332b9c24a2cd0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3639,8 +3639,6 @@ static int amdgpu_device_reset_sriov(struct amdgpu_device *adev,
 	if (r)
 		return r;
 
-	amdgpu_amdkfd_pre_reset(adev);
-
 	/* Resume IP prior to SMC */
 	r = amdgpu_device_ip_reinit_early_sriov(adev);
 	if (r)
-- 
2.20.1