On Fri, Sep 29, 2023 at 05:20:36PM -0700, D Scott Phillips wrote: > On Ampere Altra, PCIe hotplug is handled through ACPI. A side interface is > also present to request system firmware control of attention LEDs. Add an > ACPI PCI Hotplug companion driver to support attention LED control. > ... > + arm_smccc_smc(REQUEST, LED_CMD, led_status(status), LED_ATTENTION, > + pci_domain_nr(bus) | (PCI_SLOT(root_port->devfn) << 4), 0, 0, pci_domain_nr() returns "int" (normally 32 bits), but since this is an ACPI system, the domain comes from _SEG, which is defined to be 16 bits (ACPI r6.5, sec 6.5.6). So it looks like ORing in the "slot << 4" clobbers the upper 12 bits of _SEG. Is this code doing the right thing?
