From 83ef3d492840aa3eb07f28b89ba20de1bc3f58f0 Mon Sep 17 00:00:00 2001
From: fvdl <fvdl@NetBSD.org>
Date: Fri, 9 Jan 1998 22:34:58 +0000
Subject: [PATCH] Switch off CPU-PCI write posting for the Saturn chipset; it
 is known to cause problems with PCI busmasters.

---
 sys/arch/i386/pci/pchb.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/sys/arch/i386/pci/pchb.c b/sys/arch/i386/pci/pchb.c
index 2d295278cc43..791477553cad 100644
--- a/sys/arch/i386/pci/pchb.c
+++ b/sys/arch/i386/pci/pchb.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: pchb.c,v 1.9 1997/10/09 08:48:33 jtc Exp $	*/
+/*	$NetBSD: pchb.c,v 1.10 1998/01/09 22:34:58 fvdl Exp $	*/
 
 /*-
  * Copyright (c) 1996 The NetBSD Foundation, Inc.
@@ -56,6 +56,15 @@
 #define PCISET_BRIDGE_NUMBER(reg)	(((reg) >> 8) & 0xff)
 #define PCISET_PCI_BUS_NUMBER(reg)	(((reg) >> 16) & 0xff)
 
+/* XXX should be in dev/ic/i82424{reg.var}.h */
+#define I82424_CPU_BCTL_REG		0x53
+#define I82424_PCI_BCTL_REG		0x54
+
+#define I82424_BCTL_CPUMEM_POSTEN	0x01
+#define I82424_BCTL_CPUPCI_POSTEN	0x02
+#define I82424_BCTL_PCIMEM_BURSTEN	0x01
+#define I82424_BCTL_PCI_BURSTEN		0x02
+
 int	pchbmatch __P((struct device *, void *, void *));
 void	pchbattach __P((struct device *, struct device *, void *));
 
@@ -216,6 +225,17 @@ pchbattach(parent, self, aux)
 				break;
 			}
 			break;
+		case PCI_PRODUCT_INTEL_CDC:
+			bcreg = pci_conf_read(pa->pa_pc, pa->pa_tag,
+					      I82424_CPU_BCTL_REG);
+			if (bcreg & I82424_BCTL_CPUPCI_POSTEN) {
+				bcreg &= ~I82424_BCTL_CPUPCI_POSTEN;
+				pci_conf_write(pa->pa_pc, pa->pa_tag,
+					       I82424_CPU_BCTL_REG, bcreg);
+				printf("%s: disabled CPU-PCI write posting\n",
+					self->dv_xname);
+			}
+			break;
 		}
 	}
 }