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From bee3575ed41c81b7b791ef87a01413af5e2983ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Thu, 16 Jan 2020 14:06:59 +0100
Subject: drm/amdgpu: add coreboot workaround for KV/KB
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Git-commit: 77171eade8faa713c1104b29ea7ff96915ecf9fb
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Coreboot seems to have a problem correctly setting up access to the stolen VRAM
on KV/KB. Use the direct access only when necessary.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reported-and-tested-by: Fredrik Bruhn <fredrik.bruhn@unibap.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
index 19d5b133e1d7..9da9596a3638 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
@@ -381,7 +381,8 @@ static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
 	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
 
 #ifdef CONFIG_X86_64
-	if (adev->flags & AMD_IS_APU) {
+	if (adev->flags & AMD_IS_APU &&
+	    adev->gmc.real_vram_size > adev->gmc.aper_size) {
 		adev->gmc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
 		adev->gmc.aper_size = adev->gmc.real_vram_size;
 	}
-- 
2.28.0