| From 941a956b0e387b21f385f486c34ef67576775cfc Mon Sep 17 00:00:00 2001 |
| From: Andre Przywara <andre.przywara@amd.com> |
| Date: Fri, 23 Mar 2012 10:02:17 +0100 |
| Subject: hwmon: (fam15h_power) Increase output resolution |
| |
| From: Andre Przywara <andre.przywara@amd.com> |
| |
| commit 941a956b0e387b21f385f486c34ef67576775cfc upstream. |
| |
| On high CPU load the accumulating values in the running_avg_cap |
| register are very low (below 10), so averaging them too early leads |
| to unnecessary poor output resolution. Since we pretend to output |
| micro-Watt we better keep all the bits we have as long as possible. |
| |
| Signed-off-by: Andre Przywara <andre.przywara@amd.com> |
| Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> |
| Acked-by: Guenter Roeck <guenter.roeck@ericsson.com> |
| Signed-off-by: Jean Delvare <khali@linux-fr.org> |
| Signed-off-by: Tim Gardner <tim.gardner@canonical.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/hwmon/fam15h_power.c | 8 ++++---- |
| 1 file changed, 4 insertions(+), 4 deletions(-) |
| |
| --- a/drivers/hwmon/fam15h_power.c |
| +++ b/drivers/hwmon/fam15h_power.c |
| @@ -61,14 +61,14 @@ static ssize_t show_power(struct device |
| REG_TDP_RUNNING_AVERAGE, &val); |
| running_avg_capture = (val >> 4) & 0x3fffff; |
| running_avg_capture = sign_extend32(running_avg_capture, 21); |
| - running_avg_range = val & 0xf; |
| + running_avg_range = (val & 0xf) + 1; |
| |
| pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5), |
| REG_TDP_LIMIT3, &val); |
| |
| tdp_limit = val >> 16; |
| - curr_pwr_watts = tdp_limit + data->base_tdp - |
| - (s32)(running_avg_capture >> (running_avg_range + 1)); |
| + curr_pwr_watts = (tdp_limit + data->base_tdp) << running_avg_range; |
| + curr_pwr_watts -= running_avg_capture; |
| curr_pwr_watts *= data->tdp_to_watts; |
| |
| /* |
| @@ -78,7 +78,7 @@ static ssize_t show_power(struct device |
| * scaling factor 1/(2^16). For conversion we use |
| * (10^6)/(2^16) = 15625/(2^10) |
| */ |
| - curr_pwr_watts = (curr_pwr_watts * 15625) >> 10; |
| + curr_pwr_watts = (curr_pwr_watts * 15625) >> (10 + running_avg_range); |
| return sprintf(buf, "%u\n", (unsigned int) curr_pwr_watts); |
| } |
| static DEVICE_ATTR(power1_input, S_IRUGO, show_power, NULL); |
