The value of PCIBIOS_MIN_MEM reported by BIOS 1.3 on Supermicro H11SSL-i via e820__setup_pci_gap(): [mem 0xebff1000-0xfe9fffff] available for PCI devices is only suitable for a single root complex out of four (0000:00): pci_bus 0000:00: root bus resource [mem 0xec000000-0xefffffff window] pci_bus 0000:20: root bus resource [mem 0xeb800000-0xebefffff window] pci_bus 0000:40: root bus resource [mem 0xeb200000-0xeb5fffff window] pci_bus 0000:60: root bus resource [mem 0xe8b00000-0xeaffffff window] That makes the AMD EPYC 7251 unable to assign BARs of devices hot-added in those three unlucky RCs (0000:20, 0000:40 and 0000:60). If there are apertures that end below the current PCIBIOS_MIN_MEM (which is a variable pci_mem_start on x86), adjust it to the aperture's start. CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@xxxxxxxxx> --- arch/x86/pci/acpi.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index 948656069cdd..9eccb26d0bf3 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -299,6 +299,21 @@ static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci) int status; status = acpi_pci_probe_root_resources(ci); + + resource_list_for_each_entry(entry, &ci->resources) { + struct resource *res = entry->res; + + if (!(res->flags & IORESOURCE_MEM) || + res->end > pci_mem_start || + res->start == 0xa0000) + continue; + + dev_warn(&ci->root->device->dev, "Fix up PCI start address: %lx -> %llx\n", + pci_mem_start, res->start); + + pci_mem_start = res->start; + } + if (pci_use_crs) { resource_list_for_each_entry_safe(entry, tmp, &ci->resources) if (resource_is_pcicfg_ioport(entry->res)) -- 2.24.1