> -----Original Message----- > From: Jean Delvare [mailto:khali at linux-fr.org] > Sent: Tuesday, May 26, 2009 11:16 AM > To: Hans de Goede > Cc: Engelmayer Christian; lm-sensors at lm-sensors.org > Subject: Re: [PATCH v2 1/1] hwmon: Updated documentation on alarms > > On Tue, 26 May 2009 11:01:26 +0200, Hans de Goede wrote: > > On 05/25/2009 10:15 PM, Engelmayer Christian wrote: > > > From: Christian Engelmayer<christian.engelmayer at frequentis.com> > > > > > > Added fan limit alarm 'max_alarm' to the alarm section. > > > > > > > Looks good to me now, > > > > Acked-by: Hans de Goede <hdegoede at redhat.com> > > I've applied the patch now. Please note that I did have to edit it > manually so that it would apply. Christian, please fix/setup your > e-mail client so that it doesn't wrap long lines. Sorry for the inconvenience. I can see my mails being altered, although the client settings would be correct. I will fix it asap. > > One thing I am curious about is how we can have fan[1-*]_max_alarm > while we do not have fan[1-*]_max according to our documentation. Some > drivers still seem to implement this feature (dme1737, adt7470, > applesmc) so we should document it, whoulsn't we? Seems consequential. > > But the max6650 driver, which is what Christian is working on, does not > have this feature, it doesn't even have fan1_min as far as I can see. > This makes me curious about what the fan1_max_alarm and fan1_min_alarm > flags are supposed to mean for the MAX6650/1 device? Apparently not what > Documentation/hwmon/sysfs-interface says... which would be kind of > problematic. I understood the interface that the min/max alarms shall be raised when eg. a fan spins not fast enough/too fast, whereas the minimum/maximum limits are taken from the _min/_max limit files. The max6650 driver does not implement fan1_min/fan1_max because the chip does not provide support for configurable limits. The chip raises the affected alarms in case the desired speed cannot be attained in closed-loop mode. The limits are a direct result of the minimum/maximum output values supported by the DAC. eg. minimum alarm is raised in case the largest available voltage has been applied across the fan, which means that the fan is unable to spin as fast as the desired speed. That's my reasoning for choosing the mapping to fan1_min_alarm/fan1_max_alarm, although the limits are preset by the hardware and not configurable. Is that a too generous interpretation of the interface to You? > > -- > Jean Delvare
