Hi,
the current hwmon sysfs API does not specify critical or fault limits for voltage
and current readings.
Many recent power controller/monitoring chips have support for such limits in addition
to alarm limits. Typical action, when a the critical or fault limit is reached,
may be a board reset or power shutdown, or to report the fault condition.
Examples for chips supporting critical/fault limits are SMM665 and variants as well
as many PMBus devices, such as MAX8688, MAX16064, LTC2978, and others.
I think it would make sense to add critical/fault limits to the hwmon sysfs API,
to be able to report those limits if supported by a chip.
Any thoughts on this ?
Thanks,
Guenter
Hi Guenter,
On Sun, 20 Jun 2010 09:37:59 -0700, Guenter Roeck wrote:
> the current hwmon sysfs API does not specify critical or fault limits for voltage
> and current readings.
>
> Many recent power controller/monitoring chips have support for such limits in addition
> to alarm limits. Typical action, when a the critical or fault limit is reached,
> may be a board reset or power shutdown, or to report the fault condition.
>
> Examples for chips supporting critical/fault limits are SMM665 and variants as well
> as many PMBus devices, such as MAX8688, MAX16064, LTC2978, and others.
>
> I think it would make sense to add critical/fault limits to the hwmon sysfs API,
> to be able to report those limits if supported by a chip.
>
> Any thoughts on this ?
I agree it would be good to have standard names (and libsensors
support) if these features are popular. It might be a little difficult
to come up with the right attribute names though.
For temperatures, we have temp[1-*]_crit, for the critical limit on the
high end. We don't have a name for the critical limit on the low end,
because no chip ever implemented that. The name we chose doesn't offer
much possibilities for a nice name while staying consistent. Maybe
"lcrit" would be acceptable for the low end critical limit, and we keep
"crit" for the high end critical limit?
--
Jean Delvare
On Wed, Jun 23, 2010 at 08:43:46AM -0400, Jean Delvare wrote:
> Hi Guenter,
>
> On Sun, 20 Jun 2010 09:37:59 -0700, Guenter Roeck wrote:
> > the current hwmon sysfs API does not specify critical or fault limits for voltage
> > and current readings.
> >
> > Many recent power controller/monitoring chips have support for such limits in addition
> > to alarm limits. Typical action, when a the critical or fault limit is reached,
> > may be a board reset or power shutdown, or to report the fault condition.
> >
> > Examples for chips supporting critical/fault limits are SMM665 and variants as well
> > as many PMBus devices, such as MAX8688, MAX16064, LTC2978, and others.
> >
> > I think it would make sense to add critical/fault limits to the hwmon sysfs API,
> > to be able to report those limits if supported by a chip.
> >
> > Any thoughts on this ?
>
> I agree it would be good to have standard names (and libsensors
> support) if these features are popular. It might be a little difficult
> to come up with the right attribute names though.
>
> For temperatures, we have temp[1-*]_crit, for the critical limit on the
> high end. We don't have a name for the critical limit on the low end,
> because no chip ever implemented that. The name we chose doesn't offer
> much possibilities for a nice name while staying consistent. Maybe
> "lcrit" would be acceptable for the low end critical limit, and we keep
> "crit" for the high end critical limit?
>
How about {curr|in|temp}[1-*]_[min_]crit ?
In other words, keep _crit for the upper limit and introduce min_crit for the lower limit.
This would be a bit better aligned with the existing _min while maintaining _crit for the
upper limit.
Guenter
On Wed, 23 Jun 2010 06:31:47 -0700, Guenter Roeck wrote:
> On Wed, Jun 23, 2010 at 08:43:46AM -0400, Jean Delvare wrote:
> > Hi Guenter,
> >
> > On Sun, 20 Jun 2010 09:37:59 -0700, Guenter Roeck wrote:
> > > the current hwmon sysfs API does not specify critical or fault limits for voltage
> > > and current readings.
> > >
> > > Many recent power controller/monitoring chips have support for such limits in addition
> > > to alarm limits. Typical action, when a the critical or fault limit is reached,
> > > may be a board reset or power shutdown, or to report the fault condition.
> > >
> > > Examples for chips supporting critical/fault limits are SMM665 and variants as well
> > > as many PMBus devices, such as MAX8688, MAX16064, LTC2978, and others.
> > >
> > > I think it would make sense to add critical/fault limits to the hwmon sysfs API,
> > > to be able to report those limits if supported by a chip.
> > >
> > > Any thoughts on this ?
> >
> > I agree it would be good to have standard names (and libsensors
> > support) if these features are popular. It might be a little difficult
> > to come up with the right attribute names though.
> >
> > For temperatures, we have temp[1-*]_crit, for the critical limit on the
> > high end. We don't have a name for the critical limit on the low end,
> > because no chip ever implemented that. The name we chose doesn't offer
> > much possibilities for a nice name while staying consistent. Maybe
> > "lcrit" would be acceptable for the low end critical limit, and we keep
> > "crit" for the high end critical limit?
> >
> How about {curr|in|temp}[1-*]_[min_]crit ?
>
> In other words, keep _crit for the upper limit and introduce min_crit for the lower limit.
> This would be a bit better aligned with the existing _min while maintaining _crit for the
> upper limit.
I expected a counter-proposal of this kind. The problem I see is that
the new limit we are adding is unrelated to _min. However, the other
_min_* file we have (_min_alarm) expresses something which is relative
to _min. Same as _max_hyst and _crit_hyst, which are relative to _max
and _critn respectively. So I have the feeling that _min_crit sends the
wrong signal to the reader. Especially if we keep _crit for the high
bound, the asymmetry raises questions.
This is my rationale for suggesting _crit and _lcrit. Now, I won't
argue forever if others disagree, these is really only a naming
convention and everything will be fine as long as the drivers and
libsensors agree.
--
Jean Delvare
On Wed, Jun 23, 2010 at 10:29:11AM -0400, Jean Delvare wrote:
> On Wed, 23 Jun 2010 06:31:47 -0700, Guenter Roeck wrote:
> > On Wed, Jun 23, 2010 at 08:43:46AM -0400, Jean Delvare wrote:
> > > Hi Guenter,
> > >
> > > On Sun, 20 Jun 2010 09:37:59 -0700, Guenter Roeck wrote:
> > > > the current hwmon sysfs API does not specify critical or fault limits for voltage
> > > > and current readings.
> > > >
> > > > Many recent power controller/monitoring chips have support for such limits in addition
> > > > to alarm limits. Typical action, when a the critical or fault limit is reached,
> > > > may be a board reset or power shutdown, or to report the fault condition.
> > > >
> > > > Examples for chips supporting critical/fault limits are SMM665 and variants as well
> > > > as many PMBus devices, such as MAX8688, MAX16064, LTC2978, and others.
> > > >
> > > > I think it would make sense to add critical/fault limits to the hwmon sysfs API,
> > > > to be able to report those limits if supported by a chip.
> > > >
> > > > Any thoughts on this ?
> > >
> > > I agree it would be good to have standard names (and libsensors
> > > support) if these features are popular. It might be a little difficult
> > > to come up with the right attribute names though.
> > >
> > > For temperatures, we have temp[1-*]_crit, for the critical limit on the
> > > high end. We don't have a name for the critical limit on the low end,
> > > because no chip ever implemented that. The name we chose doesn't offer
> > > much possibilities for a nice name while staying consistent. Maybe
> > > "lcrit" would be acceptable for the low end critical limit, and we keep
> > > "crit" for the high end critical limit?
> > >
> > How about {curr|in|temp}[1-*]_[min_]crit ?
> >
> > In other words, keep _crit for the upper limit and introduce min_crit for the lower limit.
> > This would be a bit better aligned with the existing _min while maintaining _crit for the
> > upper limit.
>
> I expected a counter-proposal of this kind. The problem I see is that
> the new limit we are adding is unrelated to _min. However, the other
> _min_* file we have (_min_alarm) expresses something which is relative
> to _min. Same as _max_hyst and _crit_hyst, which are relative to _max
> and _critn respectively. So I have the feeling that _min_crit sends the
> wrong signal to the reader. Especially if we keep _crit for the high
> bound, the asymmetry raises questions.
>
> This is my rationale for suggesting _crit and _lcrit. Now, I won't
> argue forever if others disagree, these is really only a naming
> convention and everything will be fine as long as the drivers and
> libsensors agree.
Makes sense. No strong opinion on my side, really. Using crit/lcrit is fine for me as well.
Maybe we should wait if there is input from others and go with lcrit if there is none.
On a side note, libsensors does not support inX_fault today, even though
it is mentioned in the API, and there is no currX_fault. Likewise, libsensors supports
currX_alarm but it is not mentioned in hwmon/sysfs-interface.
Unless there are objections, I'll clean that up when I add support for the _[l]crit objects.
Also, lib/sensors.conf.5 has a comment "Likewise, tempX_crit often comes with tempX_max_crit".
Since tempX_max_crit does not exist, it might make sense to remove that comment.
Guenter
Hi Guenter,
On Wed, 23 Jun 2010 08:03:25 -0700, Guenter Roeck wrote:
> On Wed, Jun 23, 2010 at 10:29:11AM -0400, Jean Delvare wrote:
> > I expected a counter-proposal of this kind. The problem I see is that
> > the new limit we are adding is unrelated to _min. However, the other
> > _min_* file we have (_min_alarm) expresses something which is relative
> > to _min. Same as _max_hyst and _crit_hyst, which are relative to _max
> > and _critn respectively. So I have the feeling that _min_crit sends the
> > wrong signal to the reader. Especially if we keep _crit for the high
> > bound, the asymmetry raises questions.
> >
> > This is my rationale for suggesting _crit and _lcrit. Now, I won't
> > argue forever if others disagree, these is really only a naming
> > convention and everything will be fine as long as the drivers and
> > libsensors agree.
>
> Makes sense. No strong opinion on my side, really. Using crit/lcrit is fine for me as well.
> Maybe we should wait if there is input from others and go with lcrit if there is none.
OK, fine with me.
> On a side note, libsensors does not support inX_fault today, even though
> it is mentioned in the API, and there is no currX_fault. Likewise, libsensors supports
> currX_alarm but it is not mentioned in hwmon/sysfs-interface.
> Unless there are objections, I'll clean that up when I add support for the _[l]crit objects.
Yes, please!
> Also, lib/sensors.conf.5 has a comment "Likewise, tempX_crit often comes with tempX_max_crit".
> Since tempX_max_crit does not exist, it might make sense to remove that comment.
Does the sentence make sense if you replace tempX_max_crit with
tempX_crit_hyst? Looks like a copy-paste-edit mistake (that would be
from me.)
--
Jean Delvare
On Wed, Jun 23, 2010 at 12:34:37PM -0400, Jean Delvare wrote:
> Hi Guenter,
>
> On Wed, 23 Jun 2010 08:03:25 -0700, Guenter Roeck wrote:
> > On Wed, Jun 23, 2010 at 10:29:11AM -0400, Jean Delvare wrote:
> > > I expected a counter-proposal of this kind. The problem I see is that
> > > the new limit we are adding is unrelated to _min. However, the other
> > > _min_* file we have (_min_alarm) expresses something which is relative
> > > to _min. Same as _max_hyst and _crit_hyst, which are relative to _max
> > > and _critn respectively. So I have the feeling that _min_crit sends the
> > > wrong signal to the reader. Especially if we keep _crit for the high
> > > bound, the asymmetry raises questions.
> > >
> > > This is my rationale for suggesting _crit and _lcrit. Now, I won't
> > > argue forever if others disagree, these is really only a naming
> > > convention and everything will be fine as long as the drivers and
> > > libsensors agree.
> >
> > Makes sense. No strong opinion on my side, really. Using crit/lcrit is fine for me as well.
> > Maybe we should wait if there is input from others and go with lcrit if there is none.
>
> OK, fine with me.
>
> > On a side note, libsensors does not support inX_fault today, even though
> > it is mentioned in the API, and there is no currX_fault. Likewise, libsensors supports
> > currX_alarm but it is not mentioned in hwmon/sysfs-interface.
> > Unless there are objections, I'll clean that up when I add support for the _[l]crit objects.
>
> Yes, please!
>
> > Also, lib/sensors.conf.5 has a comment "Likewise, tempX_crit often comes with tempX_max_crit".
> > Since tempX_max_crit does not exist, it might make sense to remove that comment.
>
> Does the sentence make sense if you replace tempX_max_crit with
> tempX_crit_hyst? Looks like a copy-paste-edit mistake (that would be
> from me.)
Yes, I think that is the problem. I'll fix that together with the other changes.
Guenter
On Wed, Jun 23, 2010 at 02:43:46PM +0200, Jean Delvare wrote:
> For temperatures, we have temp[1-*]_crit, for the critical limit on the
> high end. We don't have a name for the critical limit on the low end,
> because no chip ever implemented that. The name we chose doesn't offer
FWIW battery monitoring chips are likely to implement under temperature
warnings - the Wolfson chargers do, for example. Low temperature can be
as problematic as high temperature for the chemistry.
On Thu, 24 Jun 2010 01:09:17 +0100, Mark Brown wrote:
> On Wed, Jun 23, 2010 at 02:43:46PM +0200, Jean Delvare wrote:
>
> > For temperatures, we have temp[1-*]_crit, for the critical limit on the
> > high end. We don't have a name for the critical limit on the low end,
> > because no chip ever implemented that. The name we chose doesn't offer
>
> FWIW battery monitoring chips are likely to implement under temperature
> warnings - the Wolfson chargers do, for example. Low temperature can be
> as problematic as high temperature for the chemistry.
We already have temp[1-*]_min. We would have to add temp[1-*]_lcrit
only if a chip has 2 lower limits, one which is only a warning and one
which is critical.
--
Jean Delvare