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-rw-r--r--drivers/ata/pata_via.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/ata/pata_via.c b/drivers/ata/pata_via.c
index 78eac276eff..0d97890af68 100644
--- a/drivers/ata/pata_via.c
+++ b/drivers/ata/pata_via.c
@@ -303,14 +303,21 @@ static void via_do_set_mode(struct ata_port *ap, struct ata_device *adev, int mo
}
/* Set UDMA unless device is not UDMA capable */
- if (udma_type && t.udma) {
- u8 cable80_status;
+ if (udma_type) {
+ u8 udma_etc;
- /* Get 80-wire cable detection bit */
- pci_read_config_byte(pdev, 0x50 + offset, &cable80_status);
- cable80_status &= 0x10;
+ pci_read_config_byte(pdev, 0x50 + offset, &udma_etc);
- pci_write_config_byte(pdev, 0x50 + offset, ut | cable80_status);
+ /* clear transfer mode bit */
+ udma_etc &= ~0x20;
+
+ if (t.udma) {
+ /* preserve 80-wire cable detection bit */
+ udma_etc &= 0x10;
+ udma_etc |= ut;
+ }
+
+ pci_write_config_byte(pdev, 0x50 + offset, udma_etc);
}
}