Re: [lm-sensors] [PATCH 4/4] hwmon: (k8temp) fix temperature

[Rudolf Marek <r.marek@assembler.cz>]

Huh interesting stuff. Any pointers to documentation please?


Andreas Herrmann napsal(a):
> Current Temperature for K8 RevG desktop CPUs is a "normalized value"
> which can be below ambient temperature.
> 
> As a consequence lots of RevG systems report temperatures like:
> 
>  sensors
>  k8temp-pci-00c3
>  Adapter: PCI adapter
>  Core0 Temp:
>               +17C
>  Core0 Temp:
>                +3C
>  Core1 Temp:
>               +21C
>  Core1 Temp:
>                +5C
> 
> being quite below ambient temperature.
> There are even reports of negative temperature values.
> 
> This patch corrects the temperature reporting of k8temp for
> RevG desktop CPUs.
> 
> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
> ---
>  drivers/hwmon/k8temp.c |   15 +++++++++++++--
>  1 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/k8temp.c b/drivers/hwmon/k8temp.c
> index 102f3ad..e37eeb5 100644
> --- a/drivers/hwmon/k8temp.c
> +++ b/drivers/hwmon/k8temp.c
> @@ -50,6 +50,7 @@ struct k8temp_data {
>  	u8 sensorsp;		/* sensor presence bits - SEL_CORE & SEL_PLACE */
>  	u32 temp[2][2];		/* core, place */
>  	u8 swap_core_select;    /* meaning of SEL_CORE is inverted */
> +	u32 temp_offset;
>  };
>  
>  static struct k8temp_data *k8temp_update_device(struct device *dev)
> @@ -117,13 +118,14 @@ static ssize_t show_temp(struct device *dev,
>  	    to_sensor_dev_attr_2(devattr);
>  	int core = attr->nr;
>  	int place = attr->index;
> +	u32 temp;
>  	struct k8temp_data *data = k8temp_update_device(dev);
>  
>  	if (data->swap_core_select)
>  		core = core ? 0 : 1;
>  
> -	return sprintf(buf, "%d\n",
> -		       TEMP_FROM_REG(data->temp[core][place]));
> +	temp = TEMP_FROM_REG(data->temp[core][place]) + data->temp_offset;

What if TEMP_FROM_REG is -3 ? temp should be imho signed.


> +	return sprintf(buf, "%d\n", temp);
>  }
>  
>  /* core, place */
> @@ -175,6 +177,15 @@ static int __devinit k8temp_probe(struct pci_dev *pdev,
>  				 "wrong - check erratum #141\n");
>  		}
>  

maybe to comment what CPU model is what

> +		if (((model >= 0x68) && (model != 0xc1)) &&
> +		    !(model = 0x68) && !(model = 0x6c) &&
> +		    !(model = 0x7c))
> +			/*
> +			 * RevG desktop CPUs (i.e. no socket S1G1 parts)
> +			 * need additional offset, otherwise reported
> +			 * temperature is below ambient temperature
> +			 */
> +			data->temp_offset = 21000;
>  
>  		break;
>  	}


Thanks,
Rudolf

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