2.6.25-stable review patch. If anyone has any objections, please let us know. ------------------ From: Tejun Heo 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 Cc: Ryan Roth Signed-off-by: Jeff Garzik Signed-off-by: Greg Kroah-Hartman --- 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; } -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/