6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maciej Kucharek [ Upstream commit 92a5184787b81e67f7b831ad860ca9b053505cf8 ] On MacBookPros with switchable graphics, the firmware puts VRAM at MC address 0 when the iGPU is enabled. A later post (S3 resume, GPU reset) moves VRAM back to the VBIOS default. gmc_v8_0 reads MC_VM_FB_LOCATION once at init and reprograms it only on SR-IOV. On bare metal, the driver then keeps using the old layout. vi_reset_quirks[] handles this for the MacBookPro14,3 by PCI ID: commit b6b1d9721851 ("drm/amdgpu: reset VI ASIC on MacBookPro14,3") Add the test that SI and CIK use: an Apple subsystem vendor and VRAM at 0. Other Polaris MacBookPros then get the same reset at load, for example the MacBookPro13,3 if its firmware leaves VRAM at 0. These boards are not tested. Keep vi_reset_quirks[]. Its MacBookPro15,1 entries fix a different failure, a module reload after S3: commit a5be7ad8f5f0 ("drm/amdgpu: reset VI ASIC on MacBookPro15,1") VRAM is not at 0 at that point, so the new test may not cover it. After the reset, FB_BASE is not 0, so the new test does not fire again on a module reload. Only compile-tested. Suggested-by: Alex Deucher Assisted-by: Claude:claude-opus-5-5 Reviewed-by: Alex Deucher Signed-off-by: Maciej Kucharek Signed-off-by: Alex Deucher (cherry picked from commit c2335b685b1e1e387f2fea1c67f56b5b8a8b6dc6) Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/amdgpu/vi.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/vi.c b/drivers/gpu/drm/amd/amdgpu/vi.c index ce54e29381079..bb81251319084 100644 --- a/drivers/gpu/drm/amd/amdgpu/vi.c +++ b/drivers/gpu/drm/amd/amdgpu/vi.c @@ -1425,6 +1425,16 @@ static bool vi_need_reset_on_init(struct amdgpu_device *adev) unsigned int i; u32 clock_cntl, pc; + /* + * MacBookPros with switchable graphics put VRAM at 0 when the iGPU + * is enabled. Any later post (S3 resume, GPU reset) moves it back to + * the vbios default, so reset and post on load to start with the + * vbios layout. + */ + if (adev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE && + !(RREG32(mmMC_VM_FB_LOCATION) & MC_VM_FB_LOCATION__FB_BASE_MASK)) + return true; + for (i = 0; i < ARRAY_SIZE(vi_reset_quirks); i++) if (adev->pdev->device == vi_reset_quirks[i].device && adev->pdev->subsystem_vendor == vi_reset_quirks[i].subsystem_vendor && -- 2.53.0