Messages in this thread | | | Date | Sun, 30 Nov 2014 01:00:00 -0800 | From | Guenter Roeck <> | Subject | Re: [PATCH] i8k: Fix temperature bug handling in i8k_get_temp() |
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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
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