libata-sff.c checks for legacy mode by testing if both primary
and secondary ports on a controller are in legacy mode and selects
legacy if either one is. However on some southbridge chips (e.g
AMD SB600/SB700) the secondary port is not wired, and when it is
disabled by setting the disable bit in the PCI header it appears
as a fixed legacy port.
Prevent incorrect detection by not testing ports that are marked
as 'dummy'
Signed-off-by: Darren Stevens <darren@xxxxxxxxxxxxxxxx>
---
v2: Changed to using 2 if statements instead of binary logic
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 051b615..09bed5d 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -2427,11 +2427,21 @@ int ata_pci_sff_activate_host(struct ata_host *host,
return rc;
if ((pdev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
- u8 tmp8, mask;
+ u8 tmp8, mask = 0;
- /* TODO: What if one channel is in native mode ... */
+ /*
+ * ATA spec says we should use legacy mode when one
+ * port is in legacy mode, but disabled ports on some
+ * PCI hosts appear as fixed legacy ports, e.g SB600/700
+ * on which the secondary port is not wired, so
+ * ignore ports that are marked as 'dummy' during
+ * this check
+ */
pci_read_config_byte(pdev, PCI_CLASS_PROG, &tmp8);
- mask = (1 << 2) | (1 << 0);
+ if (! ata_port_is_dummy(host->ports[1]))
+ mask = mask | (1 << 2);
+ if (! ata_port_is_dummy(host->ports[0]))
+ mask = mask | (1 << 0);
if ((tmp8 & mask) != mask)
legacy_mode = 1;
}
