git: 0e33c2e6df7a - main - pci: Only re-route IRQs based on firmware on x86

From: Colin Percival <cperciva_at_FreeBSD.org>
Date: Sat, 29 Mar 2025 20:18:07 UTC
The branch main has been updated by cperciva:

URL: https://cgit.FreeBSD.org/src/commit/?id=0e33c2e6df7a5de65db40c7cc0fc97f66da28ccd

commit 0e33c2e6df7a5de65db40c7cc0fc97f66da28ccd
Author:     Colin Percival <cperciva@FreeBSD.org>
AuthorDate: 2025-03-28 18:07:01 +0000
Commit:     Colin Percival <cperciva@FreeBSD.org>
CommitDate: 2025-03-29 20:17:29 +0000

    pci: Only re-route IRQs based on firmware on x86
    
    There is a (very historical) call to pci_assign_interrupt for the
    purpose of routing IRQs which may have been set up wrong by x86 BIOS
    or firmware.  On non-x86 systems, this is unnecessary; and on INTRNG
    systems it results in a (synthetic) IRQ leak and ultimately a kernel
    panic after many hotplug/unplug cycles.
    
    Suggested by:   jhb
    Reviewed by:    jhb
    MFC after:      2 weeks
    Sponsored by:   Amazon
    Differential Revision:  https://reviews.freebsd.org/D49560
---
 sys/dev/pci/pci.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index fe99d6beb029..3a51e4c38296 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -4175,6 +4175,7 @@ pci_add_resources(device_t bus, device_t dev, int force, uint32_t prefetchmask)
 		if (q->devid == devid && q->type == PCI_QUIRK_MAP_REG)
 			pci_add_map(bus, dev, q->arg1, rl, force, 0);
 
+#if defined(__i386__) || defined(__amd64__)
 	if (cfg->intpin > 0 && PCI_INTERRUPT_VALID(cfg->intline)) {
 		/*
 		 * Try to re-route interrupts. Sometimes the BIOS or
@@ -4184,6 +4185,7 @@ pci_add_resources(device_t bus, device_t dev, int force, uint32_t prefetchmask)
 		 */
 		pci_assign_interrupt(bus, dev, 1);
 	}
+#endif
 
 	if (pci_usb_takeover && pci_get_class(dev) == PCIC_SERIALBUS &&
 	    pci_get_subclass(dev) == PCIS_SERIALBUS_USB) {