PCI_EXP_DEVCAP_PAYLOAD
capa, get_payload_size(capa & PCI_EXP_DEVCAP_PAYLOAD));
pdev->pcie_mpss = FIELD_GET(PCI_EXP_DEVCAP_PAYLOAD, pdev->devcap);
pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;