| From stable-bounces@linux.kernel.org Tue May 13 01:24:07 2008 |
| From: Tejun Heo <htejun@gmail.com> |
| Date: Tue, 13 May 2008 17:23:38 +0900 |
| Subject: ata_piix: verify SIDPR access before enabling it |
| To: stable@kernel.org, Jeff Garzik l <jeff@garzik.org>, IDE/ATA development list <linux-ide@vger.kernel.org> |
| Message-ID: <4829500A.7060506@gmail.com> |
| |
| From: Tejun Heo <htejun@gmail.com> |
| |
| commit cb6716c879ecf49e2af344926c6a476821812061 upstream |
| |
| On certain configurations (certain macbooks), even though all the |
| conditions for SIDPR access described in the datasheet are met, |
| actually reading those registers just returns 0 and have no effect on |
| write. Verify SIDPR is actually working before enabling it. |
| |
| This is reported by Ryan Roth in bz#10512. |
| |
| Signed-off-by: Tejun Heo <htejun@gmail.com> |
| Cc: Ryan Roth <ryan.roth@ch2m.com> |
| Signed-off-by: Jeff Garzik <jgarzik@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/ata/ata_piix.c | 25 +++++++++++++++++++++++++ |
| 1 file changed, 25 insertions(+) |
| |
| --- a/drivers/ata/ata_piix.c |
| +++ b/drivers/ata/ata_piix.c |
| @@ -1531,6 +1531,8 @@ static void __devinit piix_init_sidpr(st |
| { |
| struct pci_dev *pdev = to_pci_dev(host->dev); |
| struct piix_host_priv *hpriv = host->private_data; |
| + struct ata_device *dev0 = &host->ports[0]->link.device[0]; |
| + u32 scontrol; |
| int i; |
| |
| /* check for availability */ |
| @@ -1549,6 +1551,29 @@ static void __devinit piix_init_sidpr(st |
| return; |
| |
| hpriv->sidpr = pcim_iomap_table(pdev)[PIIX_SIDPR_BAR]; |
| + |
| + /* SCR access via SIDPR doesn't work on some configurations. |
| + * Give it a test drive by inhibiting power save modes which |
| + * we'll do anyway. |
| + */ |
| + scontrol = piix_sidpr_read(dev0, SCR_CONTROL); |
| + |
| + /* if IPM is already 3, SCR access is probably working. Don't |
| + * un-inhibit power save modes as BIOS might have inhibited |
| + * them for a reason. |
| + */ |
| + if ((scontrol & 0xf00) != 0x300) { |
| + scontrol |= 0x300; |
| + piix_sidpr_write(dev0, SCR_CONTROL, scontrol); |
| + scontrol = piix_sidpr_read(dev0, SCR_CONTROL); |
| + |
| + if ((scontrol & 0xf00) != 0x300) { |
| + dev_printk(KERN_INFO, host->dev, "SCR access via " |
| + "SIDPR is available but doesn't work\n"); |
| + return; |
| + } |
| + } |
| + |
| host->ports[0]->ops = &piix_sidpr_sata_ops; |
| host->ports[1]->ops = &piix_sidpr_sata_ops; |
| } |