On Tue, May 12, 2026 at 06:48:40PM +0000, David Matlack wrote: > ... > + * The PCI core guarantees that preserved devices can be identified by the > same > + * bus, device, and function numbers for as long as they are preserved > + * (including across kexec). To accomplish this, the PCI core always inherits > + * the secondary and subordinate bus numbers assigned to bridges during > scanning > + * if any device is preserved. This is true even on architectures that always > + * assign new bus numbers during scanning. The kernel assumes the previous > + * kernel established a sane bus topology across kexec. > + * > + * If a misconfigured or unconfigured bridge is encountered during > enumeration > + * while there are preserved devices, itss secondary and subordinate bus > numbers > + * will be cleared and devices below it will not be enumerated.
s/itss/its/ > + * To keep things simple, inherit the secondary and subordinate bus numbers > on > + * _all_ bridges if _any_ PCI devices are preserved (i.e. even bridges > without > + * any downstream endpoints that were preserved). This avoids accidentally > + * assigning a bridge a new window that overlaps with a preserved device > that is > + * downstream of a different bridge. s/i.e. even/i.e. even/ (remove extra space)
