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authorAlan Cox <alan@redhat.com>2005-11-10 00:10:37 +0100
committerBartlomiej Zolnierkiewicz <bzolnier@gmail.com>2005-11-10 00:10:37 +0100
commit25000c2c8a6cbf9bba2de6560370ee222b4c613d (patch)
tree70a0029139c8fd8198f1ae694d124779202efecd /include
parentf5b2d8b4b5146fa2d70fec7d514fa0bd64636958 (diff)
[PATCH] ide: explain the PCI bus test we do in <asm-i386/ide.h>
Matthew Wilcox asked that this got a comment explaining why it is done so here it is. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Diffstat (limited to 'include')
-rw-r--r--include/asm-i386/ide.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/asm-i386/ide.h b/include/asm-i386/ide.h
index 79dfab87135..454440193ea 100644
--- a/include/asm-i386/ide.h
+++ b/include/asm-i386/ide.h
@@ -41,6 +41,12 @@ static __inline__ int ide_default_irq(unsigned long base)
static __inline__ unsigned long ide_default_io_base(int index)
{
+ /*
+ * If PCI is present then it is not safe to poke around
+ * the other legacy IDE ports. Only 0x1f0 and 0x170 are
+ * defined compatibility mode ports for PCI. A user can
+ * override this using ide= but we must default safe.
+ */
if (pci_find_device(PCI_ANY_ID, PCI_ANY_ID, NULL) == NULL) {
switch(index) {
case 2: return 0x1e8;