ahci: filter FPDMA non-zero offset enable for Aspire 3810T

Curiously, Aspire 3810T issues many SATA feature enable commands via
_GTF, of which one is invalid and another is not supported by the
drive.  In the process, it also enables FPDMA non-zero offset.
However, the feature also needs to be supported and enabled from the
controller and it's wrong to enable it from _GTF unless the controller
can do it by default.

Currently, this ends up enabling FPDMA non-zero offset only on the
drive side leading to NCQ command failures and eventual disabling of
NCQ.  This patch makes libata filter out FPDMA non-zero offset enable
for the machine.

This was reported by Marcus Meissner in bnc#522790.

  https://bugzilla.novell.com/show_bug.cgi?id=522790

Reported-by: Marcus Meissner <meissner@novell.com>

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index a47d309df2f2..4edca6eb73ae 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -2884,6 +2884,50 @@ static bool ahci_broken_online(struct pci_dev *pdev)
         return pdev->bus->number == (val >> 8) && pdev->devfn == (val & 0xff);
 }
 
+static void ahci_gtf_filter_workaround(struct ata_host *host)
+{
+        static const struct dmi_system_id sysids[] = {
+                /*
+                 * Aspire 3810T issues a bunch of SATA enable commands
+                 * via _GTF including an invalid one and one which is
+                 * rejected by the device.  Among the successful ones
+                 * is FPDMA non-zero offset enable which when enabled
+                 * only on the drive side leads to NCQ command
+                 * failures.  Filter it out.
+                 */
+                {
+                        .ident = "Aspire 3810T",
+                        .matches = {
+                                DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
+                                DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 3810T"),
+                        },
+                        .driver_data = (void *)ATA_ACPI_FILTER_FPDMA_OFFSET,
+                },
+                { }
+        };
+        const struct dmi_system_id *dmi = dmi_first_match(sysids);
+        unsigned int filter;
+        int i;
+
+        if (!dmi)
+                return;
+
+        filter = (unsigned long)dmi->driver_data;
+        dev_printk(KERN_INFO, host->dev,
+                   "applying extra ACPI _GTF filter 0x%x for %s\n",
+                   filter, dmi->ident);
+
+        for (i = 0; i < host->n_ports; i++) {
+                struct ata_port *ap = host->ports[i];
+                struct ata_link *link;
+                struct ata_device *dev;
+
+                ata_for_each_link(link, ap, EDGE)
+                        ata_for_each_dev(dev, link, ALL)
+                                dev->gtf_filter |= filter;
+        }
+}
+
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
         static int printed_version;
@@ -3049,6 +3093,9 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
         /* apply workaround for ASUS P5W DH Deluxe mainboard */
         ahci_p5wdh_workaround(host);
 
+        /* apply gtf filter quirk */
+        ahci_gtf_filter_workaround(host);
+
         /* initialize adapter */
         rc = ahci_configure_dma_masks(pdev, hpriv->cap & HOST_CAP_64);
         if (rc)