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authorAndre Przywara <andre.przywara@amd.com>2012-04-09 18:16:34 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-07 08:56:33 -0700
commit7d841e23feb06283577bd593ecd18113829a837c (patch)
tree43bdcaad68ed69f404bd2f4a004fe5032e45481c
parent17a766decb63b6fe4c43c06069b92b4958d7a642 (diff)
hwmon: fam15h_power: fix bogus values with current BIOSes
commit 00250ec90963b7ef6678438888f3244985ecde14 upstream. Newer BKDG[1] versions recommend a different initialization value for the running average range register in the northbridge. This improves the power reading by avoiding counter saturations resulting in bogus values for anything below about 80% of TDP power consumption. Updated BIOSes will have this new value set up from the beginning, but meanwhile we correct this value ourselves. This needs to be done on all northbridges, even on those where the driver itself does not register at. This fixes the driver on all current machines to provide proper values for idle load. [1] http://support.amd.com/us/Processor_TechDocs/42301_15h_Mod_00h-0Fh_BKDG.pdf Chapter 3.8: D18F5xE0 Processor TDP Running Average (p. 452) Signed-off-by: Andre Przywara <andre.przywara@amd.com> Acked-by: Jean Delvare <khali@linux-fr.org> [guenter.roeck@ericsson.com: Removed unnecessary return statement] Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/hwmon/fam15h_power.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
index 930370de5201..99aaf2ec5e90 100644
--- a/drivers/hwmon/fam15h_power.c
+++ b/drivers/hwmon/fam15h_power.c
@@ -122,6 +122,38 @@ 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 void __devinit tweak_runavg_range(struct pci_dev *pdev)
+{
+ u32 val;
+ const struct pci_device_id affected_device = {
+ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) };
+
+ /*
+ * 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 +187,13 @@ 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;