[patch 1/2] sata_via: Correctly setup PIO/DMA for pata slave on vt6421.

From: Bart Hartgers
Date: Sat Jan 16 2010 - 18:59:33 EST

Before only the timings for master were set. Datasheet can be found
here: ftp://ftp.vtbridge.org/Docs/Storage/DS_VT6421A_100_CCPL.PDF
Surprisingly, a slave drive works without this patch. According to the
datasheet, the controller by default derives the DMA mode from the
Set Features command issued to a drive. Not sure about the PIO
timings, though. The real problem is that the timings for the master
effectively are the ones tuned for the slave. If these support
different UDMA-settings, there is trouble, especially when the slave
supports a higher UDMA than the master.

Anyhow, using the same mechanism for both master and slave seems like
a good idea.

Signed-off-by: Bart Hartgers <bart.hartgers@xxxxxxxxx>
Index: linux-2.6.33-rc4/drivers/ata/sata_via.c
--- linux-2.6.33-rc4.orig/drivers/ata/sata_via.c 2010-01-16 22:28:13.000000000 +0100
+++ linux-2.6.33-rc4/drivers/ata/sata_via.c 2010-01-16 22:29:30.000000000 +0100
@@ -44,7 +44,7 @@
#include <linux/libata.h>

#define DRV_NAME "sata_via"
-#define DRV_VERSION "2.4"
+#define DRV_VERSION "2.5"

* vt8251 is different from other sata controllers of VIA. It has two
@@ -392,14 +392,16 @@ static void vt6421_set_pio_mode(struct a
struct pci_dev *pdev = to_pci_dev(ap->host->dev);
static const u8 pio_bits[] = { 0xA8, 0x65, 0x65, 0x31, 0x20 };
- pci_write_config_byte(pdev, PATA_PIO_TIMING, pio_bits[adev->pio_mode - XFER_PIO_0]);
+ pci_write_config_byte(pdev, PATA_PIO_TIMING - adev->devno,
+ pio_bits[adev->pio_mode - XFER_PIO_0]);

static void vt6421_set_dma_mode(struct ata_port *ap, struct ata_device *adev)
struct pci_dev *pdev = to_pci_dev(ap->host->dev);
static const u8 udma_bits[] = { 0xEE, 0xE8, 0xE6, 0xE4, 0xE2, 0xE1, 0xE0, 0xE0 };
- pci_write_config_byte(pdev, PATA_UDMA_TIMING, udma_bits[adev->dma_mode - XFER_UDMA_0]);
+ pci_write_config_byte(pdev, PATA_UDMA_TIMING - adev->devno,
+ udma_bits[adev->dma_mode - XFER_UDMA_0]);

static const unsigned int svia_bar_sizes[] = {

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/