From: Young_X <YangX92@xxxxxxxxxxx>
If we assign an amd device to a virtual mechine, we can no longer
assume a fixed hardware topology, like the GPU having a parent device.
This patch simply adds pci_is_root_bus() tests to avoid passing a
NULL pointer to PCI access functions.
See commit e79d5c0870ee ("drm/amdgpu: check before checking pci bridge
registers") and commit 0bd252de78d4 ("radeon: Test for PCI root bus
before assuming bus->self") for details.
Signed-off-by: Young_X <YangX92@xxxxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/cik.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/cik.c b/drivers/gpu/drm/amd/amdgpu/cik.c
index f41f5f5..8b51fa8 100644
--- a/drivers/gpu/drm/amd/amdgpu/cik.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik.c
@@ -1622,7 +1622,8 @@ static void cik_program_aspm(struct amdgpu_device *adev)
if (orig != data)
WREG32_PCIE(ixPCIE_LC_LINK_WIDTH_CNTL, data);
- if (!disable_clkreq) {
+ if (!disable_clkreq &&
+ !pci_is_root_bus(adev->pdev->bus)) {
struct pci_dev *root = adev->pdev->bus->self;
u32 lnkcap;
--
2.7.4
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