[PATCH] libata: add a dummy set_mode() in pata_pcmcia

[Arnd Bergmann <arnd@arndb.de>]

CompactFlash cards in a passive PCMCIA adapter don't seem
to like the ATA_CMD_SET_FEATURES command, which causes
libata device probing to fail.

Since PCMCIA only allows PIO mode 0 anyway, there is no
point in ever setting a higher speed. Adding the dummy
function seems to do the right thing.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---

This bug was reported earlier in 
http://bugzilla.kernel.org/show_bug.cgi?id=7711 by 
wkl@informatik.uni-kiel.de.

I have not been able to find out _why_ all my CF cards reject
the SETFEATURES_XFER command, but I have verified that the
same happens when trying to use hdparm with ide_cs.

Note that none of my cards are CF-4.0 compliant, so they
also don't do UDMA modes. The highest mode claimed to be
supported by one of my cards is PIO-4, but I can't set
it into any of the modes it likes.

diff --git a/drivers/ata/pata_pcmcia.c b/drivers/ata/pata_pcmcia.c
index 9ed7f58..642753c 100644
--- a/drivers/ata/pata_pcmcia.c
+++ b/drivers/ata/pata_pcmcia.c
@@ -44,6 +44,30 @@
 #define DRV_NAME "pata_pcmcia"
 #define DRV_VERSION "0.2.11"
 
+/**
+ *	legacy_set_mode		-	mode setting
+ *	@ap: IDE interface
+ *
+ *	Use a non standard set_mode function. We don't want to be tuned.
+ *
+ *	PCMCIA support only PIO0 transfers and cards may return an error
+ *	if you attempt to set that explicitly.
+ */
+
+static void pcmcia_set_mode(struct ata_port *ap)
+{
+	int i;
+
+	for (i = 0; i < ATA_MAX_DEVICES; i++) {
+		struct ata_device *dev = &ap->device[i];
+		if (ata_dev_enabled(dev)) {
+			dev->pio_mode = XFER_PIO_0;
+			dev->xfer_mode = XFER_PIO_0;
+			dev->xfer_shift = ATA_SHIFT_PIO;
+			dev->flags |= ATA_DFLAG_PIO;
+		}
+	}
+}
 /*
  *	Private data structure to glue stuff together
  */
@@ -79,6 +103,7 @@ static struct ata_port_operations pcmcia_port_ops = {
 	.check_status 	= ata_check_status,
 	.exec_command	= ata_exec_command,
 	.dev_select 	= ata_std_dev_select,
+	.set_mode	= pcmcia_set_mode,
 
 	.freeze		= ata_bmdma_freeze,
 	.thaw		= ata_bmdma_thaw,