Hello, On Wed, Jul 08, 2026 at 02:35:14PM -0500, Mario Limonciello wrote: > On systems where PCI bus renumbering occurs (e.g. pci=realloc, > resource conflicts), the runtime bus number may differ from the > BIOS POST bus number recorded in the VFCT table. This causes > amdgpu_acpi_vfct_bios() to fail finding the VBIOS even though > the correct device entry exists. > > Introduce amdgpu_acpi_vfct_match() which treats the bus number > as a soft filter: vendor/device/function identity is the hard > requirement, while exact bus match is the preferred path. When > bus numbers disagree but device identity matches, accept the > VFCT entry and log a dev_notice for diagnostics. > > Reported-by: Oz Tiram <[email protected]> > Closes: > https://lore.kernel.org/amd-gfx/[email protected]/ > Signed-off-by: Mario Limonciello <[email protected]> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c | 45 +++++++++++++++++++++--- > 1 file changed, 40 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c > index 3ebdd792feec1..d8fd047295d9d 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c > @@ -377,6 +377,45 @@ static bool amdgpu_read_disabled_bios(struct > amdgpu_device *adev) > false : amdgpu_asic_read_disabled_bios(adev); > } > > +/** > + * amdgpu_acpi_vfct_match() - Check if a VFCT entry matches the device > + * @adev: AMDGPU device > + * @vhdr: VFCT image header to check > + * > + * VFCT entries contain the PCI bus number as recorded during BIOS POST. > + * On systems where the kernel renumbers PCI buses (e.g. pci=realloc or > + * resource conflicts), the runtime bus number may differ from the POST > + * value. Match by device identity (vendor + device + function) and use > + * the bus number as a preference: exact bus match is preferred, but when > + * the bus numbers disagree we accept the entry if the device identity > + * matches. > + * > + * Returns: 0 on match, -ENODEV on no match > + */ > +static int amdgpu_acpi_vfct_match(struct amdgpu_device *adev, > + VFCT_IMAGE_HEADER *vhdr) > +{ > + /* Vendor and device IDs must always match */ > + if (vhdr->VendorID != adev->pdev->vendor || > + vhdr->DeviceID != adev->pdev->device) > + return -ENODEV; > + > + if (vhdr->PCIDevice != PCI_SLOT(adev->pdev->devfn) || > + vhdr->PCIFunction != PCI_FUNC(adev->pdev->devfn)) > + return -ENODEV; > + > + /* Exact bus number match - preferred */ > + if (vhdr->PCIBus == adev->pdev->bus->number) > + return 0; > + > + /* Bus mismatch but device identity matches (PCI renumbering case) */ > + dev_notice(adev->dev, > + "VFCT bus number mismatch: table %u != runtime %u, matching > by device identity (vendor 0x%04x device 0x%04x)\n", > + vhdr->PCIBus, adev->pdev->bus->number, > + adev->pdev->vendor, adev->pdev->device); > + return 0; > +} > + > #ifdef CONFIG_ACPI > static bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev) > { > @@ -413,11 +452,7 @@ static bool amdgpu_acpi_vfct_bios(struct amdgpu_device > *adev) > } > > if (vhdr->ImageLength && > - vhdr->PCIBus == adev->pdev->bus->number && > - vhdr->PCIDevice == PCI_SLOT(adev->pdev->devfn) && > - vhdr->PCIFunction == PCI_FUNC(adev->pdev->devfn) && > - vhdr->VendorID == adev->pdev->vendor && > - vhdr->DeviceID == adev->pdev->device) { > + !amdgpu_acpi_vfct_match(adev, vhdr)) { > adev->bios = kmemdup(&vbios->VbiosContent, > vhdr->ImageLength, > GFP_KERNEL);
For the record to hopefully make it easier for others to find the fix:
This patch became 33a18ecd2fbf in
https://gitlab.freedesktop.org/agd5f/linux.git drm-next
and thus next and it introduces a build failure for !CONFIG_ACPI builds:
drivers/gpu/drm/radeon/radeon_bios.c:614:12: error:
‘radeon_acpi_vfct_match’ defined but not used [-Werror=unused-function]
614 | static int radeon_acpi_vfct_match(struct radeon_device *rdev,
| ^~~~~~~~~~~~~~~~~~~~~~
Patch available at
https://lore.kernel.org/all/[email protected]/
Best regards
Uwe
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