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path: root/drivers/hwmon/fam15h_power.c
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Diffstat (limited to 'drivers/hwmon/fam15h_power.c')
-rw-r--r--drivers/hwmon/fam15h_power.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
index b7494af1e4a9..e8e18cab1fb8 100644
--- a/drivers/hwmon/fam15h_power.c
+++ b/drivers/hwmon/fam15h_power.c
@@ -122,6 +122,41 @@ static bool __devinit fam15h_power_is_internal_node0(struct pci_dev *f4)
return true;
}
+/*
+ * Newer BKDG versions have an updated recommendation on how to properly
+ * initialize the running average range (was: 0xE, now: 0x9). This avoids
+ * counter saturations resulting in bogus power readings.
+ * We correct this value ourselves to cope with older BIOSes.
+ */
+static DEFINE_PCI_DEVICE_TABLE(affected_device) = {
+ { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
+ { 0 }
+};
+
+static void __devinit tweak_runavg_range(struct pci_dev *pdev)
+{
+ u32 val;
+
+ /*
+ * let this quirk apply only to the current version of the
+ * northbridge, since future versions may change the behavior
+ */
+ if (!pci_match_id(affected_device, pdev))
+ return;
+
+ pci_bus_read_config_dword(pdev->bus,
+ PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
+ REG_TDP_RUNNING_AVERAGE, &val);
+ if ((val & 0xf) != 0xe)
+ return;
+
+ val &= ~0xf;
+ val |= 0x9;
+ pci_bus_write_config_dword(pdev->bus,
+ PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
+ REG_TDP_RUNNING_AVERAGE, val);
+}
+
static void __devinit fam15h_power_init_data(struct pci_dev *f4,
struct fam15h_power_data *data)
{
@@ -155,6 +190,13 @@ static int __devinit fam15h_power_probe(struct pci_dev *pdev,
struct device *dev;
int err;
+ /*
+ * though we ignore every other northbridge, we still have to
+ * do the tweaking on _each_ node in MCM processors as the counters
+ * are working hand-in-hand
+ */
+ tweak_runavg_range(pdev);
+
if (!fam15h_power_is_internal_node0(pdev)) {
err = -ENODEV;
goto exit;