sata_via: magic vt6421 fix for transmission problems w/ WD drives
vt6421 has problems talking to recent WD drives. It causes a lot of
transmission errors while high bandwidth transfer as reported in the
following bugzilla entry.
https://bugzilla.kernel.org/show_bug.cgi?id=15173
Joseph Chan provided the following fix. I don't have any idea what it
does but I can verify the issue is gone with the patch applied.
Signed-off-by: Tejun Heo <tj@kernel.org>
Originally-from: Joseph Chan <JosephChan@via.com.tw>
Reported-by: Jorrit Tijben <sjorrit@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/sata_via.c b/drivers/ata/sata_via.c
index 101d8c2..0ecd0f6 100644
--- a/drivers/ata/sata_via.c
+++ b/drivers/ata/sata_via.c
@@ -575,6 +575,19 @@
tmp8 |= NATIVE_MODE_ALL;
pci_write_config_byte(pdev, SATA_NATIVE_MODE, tmp8);
}
+
+ /*
+ * vt6421 has problems talking to some drives. The following
+ * is the magic fix from Joseph Chan <JosephChan@via.com.tw>.
+ * Please add proper documentation if possible.
+ *
+ * https://bugzilla.kernel.org/show_bug.cgi?id=15173
+ */
+ if (pdev->device == 0x3249) {
+ pci_read_config_byte(pdev, 0x52, &tmp8);
+ tmp8 |= 1 << 2;
+ pci_write_config_byte(pdev, 0x52, tmp8);
+ }
}
static int svia_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)