Module Name:    src
Committed By:   martin
Date:           Wed Aug 23 17:09:09 UTC 2023

Modified Files:
        src/sys/arch/x86/pci [netbsd-9]: pci_machdep.c

Log Message:
Pull up following revision(s) (requested by msaitoh in ticket #1722):

        sys/arch/x86/pci/pci_machdep.c: revision 1.94

Fix detection of availability of MSI/MSI-X on some systems.

Try to find all functions on bus 0, device 0 to find a PCI host bridge.
Some CPU's host bridge is at 0:0.4. Tested by Intel Snow Ridge.


To generate a diff of this commit:
cvs rdiff -u -r1.86 -r1.86.2.1 src/sys/arch/x86/pci/pci_machdep.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/arch/x86/pci/pci_machdep.c
diff -u src/sys/arch/x86/pci/pci_machdep.c:1.86 src/sys/arch/x86/pci/pci_machdep.c:1.86.2.1
--- src/sys/arch/x86/pci/pci_machdep.c:1.86	Fri May 24 14:28:48 2019
+++ src/sys/arch/x86/pci/pci_machdep.c	Wed Aug 23 17:09:09 2023
@@ -1,4 +1,4 @@
-/*	$NetBSD: pci_machdep.c,v 1.86 2019/05/24 14:28:48 nonaka Exp $	*/
+/*	$NetBSD: pci_machdep.c,v 1.86.2.1 2023/08/23 17:09:09 martin Exp $	*/
 
 /*-
  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
@@ -73,7 +73,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pci_machdep.c,v 1.86 2019/05/24 14:28:48 nonaka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pci_machdep.c,v 1.86.2.1 2023/08/23 17:09:09 martin Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -485,6 +485,8 @@ pci_attach_hook(device_t parent, device_
 	pci_chipset_tag_t pc = pba->pba_pc;
 	pcitag_t tag;
 	pcireg_t id, class;
+	int i;
+	bool havehb = false;
 #endif
 
 	if (pba->pba_bus == 0)
@@ -502,19 +504,25 @@ pci_attach_hook(device_t parent, device_
 #ifdef __HAVE_PCI_MSI_MSIX
 	/*
 	 * In order to decide whether the system supports MSI we look
-	 * at the host bridge, which should be device 0 function 0 on
-	 * bus 0.  It is better to not enable MSI on systems that
+	 * at the host bridge, which should be device 0 on bus 0.
+	 * It is better to not enable MSI on systems that
 	 * support it than the other way around, so be conservative
 	 * here.  So we don't enable MSI if we don't find a host
 	 * bridge there.  We also deliberately don't enable MSI on
 	 * chipsets from low-end manifacturers like VIA and SiS.
 	 */
-	tag = pci_make_tag(pc, 0, 0, 0);
-	id = pci_conf_read(pc, tag, PCI_ID_REG);
-	class = pci_conf_read(pc, tag, PCI_CLASS_REG);
-
-	if (PCI_CLASS(class) != PCI_CLASS_BRIDGE ||
-	    PCI_SUBCLASS(class) != PCI_SUBCLASS_BRIDGE_HOST)
+	for (i = 0; i <= 7; i++) {
+		tag = pci_make_tag(pc, 0, 0, i);
+		id = pci_conf_read(pc, tag, PCI_ID_REG);
+		class = pci_conf_read(pc, tag, PCI_CLASS_REG);
+
+		if (PCI_CLASS(class) == PCI_CLASS_BRIDGE &&
+		    PCI_SUBCLASS(class) == PCI_SUBCLASS_BRIDGE_HOST) {
+			havehb = true;
+			break;
+		}
+	}
+	if (havehb == false)
 		return;
 
 	/* VMware and KVM use old chipset, but they can use MSI/MSI-X */

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