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Diffstat (limited to 'arch/x86/include/asm/pci_x86.h')
-rw-r--r--arch/x86/include/asm/pci_x86.h10
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index fa1195dae425..46873fbd44e1 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -151,11 +151,11 @@ extern struct list_head pci_mmcfg_list;
#define PCI_MMCFG_BUS_OFFSET(bus) ((bus) << 20)
/*
- * AMD Fam10h CPUs are buggy, and cannot access MMIO config space
- * on their northbrige except through the * %eax register. As such, you MUST
- * NOT use normal IOMEM accesses, you need to only use the magic mmio-config
- * accessor functions.
- * In fact just use pci_config_*, nothing else please.
+ * On AMD Fam10h CPUs, all PCI MMIO configuration space accesses must use
+ * %eax. No other source or target registers may be used. The following
+ * mmio_config_* accessors enforce this. See "BIOS and Kernel Developer's
+ * Guide (BKDG) For AMD Family 10h Processors", rev. 3.48, sec 2.11.1,
+ * "MMIO Configuration Coding Requirements".
*/
static inline unsigned char mmio_config_readb(void __iomem *pos)
{