From: Guenter Roeck <linux@roeck-us.net>
To: "Pali Rohár" <pali.rohar@gmail.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>
Cc: Steven Honeyman <stevenhoneyman@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] i8k: Fix temperature bug handling in i8k_get_temp()
Date: Sun, 30 Nov 2014 01:00:00 -0800 [thread overview]
Message-ID: <547ADC90.8000507@roeck-us.net> (raw)
In-Reply-To: <1416322614-10308-1-git-send-email-pali.rohar@gmail.com>
On 11/18/2014 06:56 AM, Pali Rohár wrote:
> Static array prev[] was incorrectly initialized. It should be initialized to
> some "invalid" temperature value (above I8K_MAX_TEMP).
>
> Next, function should store "invalid" value to prev[] (above I8K_MAX_TEMP),
> not valid (= I8K_MAX_TEMP) because whole temperature bug handling will not
> work.
>
> And last part, to not break existing detection of temperature sensors, register
> them also if i8k report too high temperature (above I8K_MAX_TEMP). This is
> needed because some sensors are sometimes turned off (e.g sensor on GPU which
> can be turned off/on) and in this case SMM report too high value.
>
> To prevent reporting "invalid" values to userspace, return -EINVAL. In this case
> sensors which are currently turned off (e.g optimus/powerexpress/enduro gpu)
> are reported as "N/A" by lm-sensors package.
>
> Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> ---
> drivers/char/i8k.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
> index 7272b08..e34a019 100644
> --- a/drivers/char/i8k.c
> +++ b/drivers/char/i8k.c
> @@ -298,7 +298,7 @@ static int i8k_get_temp(int sensor)
> int temp;
>
> #ifdef I8K_TEMPERATURE_BUG
> - static int prev[4];
> + static int prev[4] = { I8K_MAX_TEMP+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1 };
> #endif
> regs.ebx = sensor & 0xff;
> rc = i8k_smm(®s);
> @@ -317,10 +317,12 @@ static int i8k_get_temp(int sensor)
> */
> if (temp > I8K_MAX_TEMP) {
> temp = prev[sensor];
> - prev[sensor] = I8K_MAX_TEMP;
> + prev[sensor] = I8K_MAX_TEMP+1;
> } else {
> prev[sensor] = temp;
> }
> + if (temp > I8K_MAX_TEMP)
> + return -ERANGE;
Can we return -ENODATA in this case ? I think that would be more appropriate.
> #endif
>
> return temp;
> @@ -499,6 +501,8 @@ static ssize_t i8k_hwmon_show_temp(struct device *dev,
> int temp;
>
> temp = i8k_get_temp(index);
> + if (temp == -ERANGE)
> + return -EINVAL;
and can we also return -ENODATA to user space ?
This would make the code a bit cleaner.
Thanks,
Guenter
next prev parent reply other threads:[~2014-11-30 9:00 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-19 14:46 [PATCH] i8k: Ignore temperature sensors which report invalid values Pali Rohár
2014-10-19 15:13 ` Guenter Roeck
2014-10-20 16:46 ` Pali Rohár
2014-10-21 4:27 ` Guenter Roeck
2014-10-22 12:29 ` Pali Rohár
2014-10-22 16:19 ` Guenter Roeck
2014-10-22 16:35 ` Pali Rohár
2014-10-22 17:10 ` Guenter Roeck
2014-10-23 10:37 ` Pali Rohár
2014-10-23 16:45 ` Guenter Roeck
2014-11-17 8:35 ` Pali Rohár
2014-11-18 5:56 ` Guenter Roeck
2014-11-18 14:46 ` Pali Rohár
2014-11-18 14:56 ` [PATCH] i8k: Fix temperature bug handling in i8k_get_temp() Pali Rohár
2014-11-30 0:12 ` Guenter Roeck
2014-11-30 14:44 ` Pali Rohár
2014-11-30 9:00 ` Guenter Roeck [this message]
2014-11-30 14:48 ` Pali Rohár
2014-11-30 15:56 ` Guenter Roeck
2014-11-30 16:00 ` Pali Rohár
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