[lm-sensors] Need some guidance on adhering to the sysfs standards

Juerg Haefliger juergh at gmail.com
Sun Apr 22 22:41:00 CEST 2007


On 4/22/07, Hans de Goede <j.w.r.degoede at hhs.nl> wrote:
> Juerg Haefliger wrote:
> > Hi Jean,
> >
> > On 4/22/07, Jean Delvare <khali at linux-fr.org> wrote:
> >> Hi Juerg,
> >>
> >> On Thu, 19 Apr 2007 12:04:28 -0700, Juerg Haefliger wrote:
> >>> George, Jean,
> >>>
> >>> I'm struggling with the same issue for the DME1737 I'm currently
> >>> working on. This chip also features temp zones and "hottest of x,y,z"
> >>> PWM control. The current sysfs standard is not flexible enough to
> >>> handle these features, especially the combination of a single PWM
> >>> being controlled by multiple temp inputs and multiple PMWs being
> >>> controlled by the same temp input. I believe we need another layer of
> >>> mapping. I.e. temp->pwm is not sufficient, but rather temp->zone->pwm.
> >>>
> >>> I therefore propose the add the following sysfs attributes to our standard:
> >>>
> >>> zone[1-*]_auto_channels_temp   for temp-to-zone mapping
> >>> pwm[1-*]_auto_channels_zone   for zone-to-pwm mapping
> >>> zone[1-*]_auto_point[1-*]_temp   for zone temp auto points.
> >> I don't see what value it adds compared to what we currently have.
> >>
> >> We have pwm[1-*]_auto_channels_temp, which is a bit vector. We have one
> >> file per PWM, one bit per temperature channel, so all in all we have a
> >> Npwm x Ntemp matrix, or N-N relation between PWM and temperatures. This
> >> already allows us to handle cases such as "the hottest of tempA and
> >> tempB control pwmC" or "tempD controls pwmE and pwmF".
> >
> > Yes, I understand that.
> >
> >
> >> You propose to add the concept of zone. According to the above, each
> >> zone could include any temperature channel, so we have a N-N relation
> >> between zones and temperatures. Then you express another N-N relation
> >> between PWM channels and zones. As far as I can see, this results in a
> >> N-N relation between temperatures and PWM, just expressed differently.
> >> Am I missing something? What do you think it would let us express,
> >> which the current model doesn't?
> >
> > What I can't seem to map to our current standard (or maybe I just
> > don't see it) is the concept of multiple sets of thermal thresholds
> > for a single temp input. Example: pwm2 is controlled by zone2 and pwm3
> > is controlled by zone3 but both zone2 and zone3 are controlled by
> > temp3. Both zone2 & 3 have different thermal thresholds.
> >
> > With the current standard I can only apply one set of thresholds to
> > temp3 via temp3_auto_point[1-*]_temp.
> >
>
> Thats easy, AFAIK you can have either temp[1-*]_auto_point[1-*]_temp,
> or pwm[1-*]_auto_point[1-*]_temp, iow you can couple the autopoints
> to either a temp channel or a pwm channel depending on if the
> thresholds are set per temp channel or per pwm channel.

That's not going to work. I can't use temp[1-*]_auto_point[1-*]_temp
because there are multiple sets of thresholds for a single temp input
and I can't use pwm[1-*]_auto_point[1-*]_temp either because then the
"hottest of x,y,z" doesn't work.

...juerg


> I'm not 100% sure though, so lets wait what others have to say too.
>
> Regards,
>
> Hans
>




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