Re: [lm-sensors] The new thermal management sysfs class, and hwmon

Hans de Goede
2008-02-22T11:00:58Z

Zhang, Rui wrote:
> Hi, Hans,
>
> On Fri, 2008-02-22 at 16:00 +0800, Hans de Goede wrote:
>
>> I think all that is really needed and asked for is for the new thermal
>> ACPI
>> code to:
>> 1) provide temp readings in the same format as hwmon (so milli degrees
>> celcius,
>> not degrees celcius
> Agree.
>> 2) provide a hwmon interface so that tools like (but not limited too):
>> * net-snmp
>> * mrtg
>> * sensors
>> * sensors-applet (gnome)
>> * xfce-sensors-applet
>> * ksysguard
>> * ksensors
>> * gkrellm
>>
>> Can provide temp and fan readings without having to be modified.
> hmm, for fan device, maybe something like this?
> pwm[1-*]_enable = 1 : manual fan control (using pwm[1-*])
> 2+: automatic fan control (by acpi thermal driver)
> pwm[1-*] = 0 : fan is off.
> pwm[1-*] = 255: fan is on.
> pwm[1-*] has only two valid values as ACPI fan only support
> two states, ON/OFF. and it doesn't need fan[1-*]_input because the fan
> speed is not available.
> Yes, it can work for ACPI fan although I don't think the existing pwm
> hwmon I/F maps well to what we need and it seems like a "forced fit" to
> use it. Any better ideas? :)
>

I wouldn't expose a pwm interface, doing so isn't that important as none of the
above listed apps actually use it, the pwm interface really only is for people
who want to manually tweak their fan speed and / or use some scripts to control
the fan speed based on temp when the hardware doesn't support it, as such it
doesn't get widely used, also since there isn't a really good mapping between
acpi thermalzone stuff and the hwmon pwm interface I wouldn't add a pwm
interface to a hwmon interface the the thermal zone code.

And if fan speeds aren't available (aren't they?) then I would only add a hwmon
class reference to a sysfs dir containing tempX_input's and a name atrribute
and leave it at that.

But thats just my 2 euro-cents

Regards,

Hans