CVE-2025-21831

In the Linux kernel, the following vulnerability has been resolved: PCI: Avoid putting some root ports into D3 on TUXEDO Sirius Gen1 commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend") sets the policy that all PCIe ports are allowed to use D3. When the system is suspended if the port is not power manageable by the platform and won't be used for wakeup via a PME this sets up the policy for these ports to go into D3hot. This policy generally makes sense from an OSPM perspective but it leads to problems with wakeup from suspend on the TUXEDO Sirius 16 Gen 1 with a specific old BIOS. This manifests as a system hang. On the affected Device + BIOS combination, add a quirk for the root port of the problematic controller to ensure that these root ports are not put into D3hot at suspend. This patch is based on https://lore.kernel.org/linux-pci/[email protected] but with the added condition both in the documentation and in the code to apply only to the TUXEDO Sirius 16 Gen 1 with a specific old BIOS and only the affected root ports.