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| author | Alan Cox <alan@redhat.com> | 2005-11-10 00:10:37 +0100 |
|---|---|---|
| committer | Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> | 2005-11-10 00:10:37 +0100 |
| commit | 25000c2c8a6cbf9bba2de6560370ee222b4c613d (patch) | |
| tree | 70a0029139c8fd8198f1ae694d124779202efecd | |
| parent | f5b2d8b4b5146fa2d70fec7d514fa0bd64636958 (diff) | |
| download | linux-25000c2c8a6cbf9bba2de6560370ee222b4c613d.tar.gz linux-25000c2c8a6cbf9bba2de6560370ee222b4c613d.tar.bz2 linux-25000c2c8a6cbf9bba2de6560370ee222b4c613d.zip | |
[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>
| -rw-r--r-- | include/asm-i386/ide.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/asm-i386/ide.h b/include/asm-i386/ide.h index 79dfab87135d..454440193eac 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; |