diff options
| -rw-r--r-- | arch/x86/pci/acpi.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index cd8f47c0d97e..a4f43054bc79 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -200,6 +200,27 @@ void __init pci_acpi_crs_quirks(void) if (year >= 0 && year < 2008 && iomem_resource.end <= 0xffffffff) pci_use_crs = false; + /* + * Some firmware includes unusable space (host bridge registers, + * hidden PCI device BARs, etc) in PCI host bridge _CRS. This is a + * firmware defect, and 4dc2287c1805 ("x86: avoid E820 regions when + * allocating address space") has clipped out the unusable space in + * the past. + * + * But other firmware supplies E820 reserved regions that cover + * entire _CRS windows, so clipping throws away the entire window, + * leaving none for hot-added or uninitialized devices. These E820 + * entries are probably *not* a firmware defect, so disable the + * clipping by default for post-2022 machines. + * + * We already have quirks to disable clipping for pre-2023 + * machines, and we'll likely need quirks to *enable* clipping for + * post-2022 machines that incorrectly include unusable space in + * _CRS. + */ + if (year >= 2023) + pci_use_e820 = false; + dmi_check_system(pci_crs_quirks); /* |