[PATCH] drm/amdgpu: add coreboot workaround for KV/KB

[Christian König]

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 at amd.com>
---
 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;
 	}
-- 
2.17.1