linux-kernel - Re: [PATCH] hwmon: (k10temp) Report negative temperatures

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Date:   Tue, 23 May 2023 14:46:43 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Baskaran Kannan <Baski.Kannan@....com>
Cc:     babu.moger@....com, clemens@...isch.de, jdelvare@...e.com,
        linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hwmon: (k10temp) Report negative temperatures

On Tue, May 23, 2023 at 03:49:32PM -0500, Baskaran Kannan wrote:
> Currently, the tctl and die temperatures are rounded off to zero
> if they are less than 0. There are industrial processors which work
> below zero.

This was introduced with commit aef17ca12719 ("hwmon: (k10temp) Only apply
temperature offset if result is positive"). This patch would effecively
revert that change. Given the reason for introducing it I am not convinced
that it is a good idea to unconditionally revert it.

Guenter

> 
> To display the correct temperature remove the rounding off.
> 
> Signed-off-by: Baskaran Kannan <Baski.Kannan@....com>
> ---
>  drivers/hwmon/k10temp.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/hwmon/k10temp.c b/drivers/hwmon/k10temp.c
> index 7b177b9fbb09..489ad0b1bc74 100644
> --- a/drivers/hwmon/k10temp.c
> +++ b/drivers/hwmon/k10temp.c
> @@ -204,13 +204,9 @@ static int k10temp_read_temp(struct device *dev, u32 attr, int channel,
>  		switch (channel) {
>  		case 0:		/* Tctl */
>  			*val = get_raw_temp(data);
> -			if (*val < 0)
> -				*val = 0;
>  			break;
>  		case 1:		/* Tdie */
>  			*val = get_raw_temp(data) - data->temp_offset;
> -			if (*val < 0)
> -				*val = 0;
>  			break;
>  		case 2 ... 13:		/* Tccd{1-12} */
>  			amd_smn_read(amd_pci_dev_to_node_id(data->pdev),
> -- 
> 2.25.1
>