Messages in this thread | | | Date | Tue, 28 Aug 2007 13:19:42 +0200 | From | Jean Delvare <> | Subject | Re: [lm-sensors] [PATCH] v1 of IBM power meter driver |
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Hi Darrick, hi Henrique,
Good thing that manufacturers start including wattmeters in their hardware. Hopefully this will help users better control their power consumption in the long run.
On Mon, 27 Aug 2007 22:50:29 -0300, Henrique de Moraes Holschuh wrote: > On Mon, 27 Aug 2007, Darrick J. Wong wrote: > > documentation doesn't mention any naming conventions for sensors that > > measure Watts, so I am proposing that they be called "powerX_input" in a > > fashion similar to temperature/rpm/current sensors. If that is > > agreeable to everyone, I'll post a follow-up patch to amend the > > documentation. > > What unit should we use? Watts are way, way too big as there is no > floating/fixed point in sysfs. 10^-6 W is probably what is called for, > since we already need 10^-3 V and 10^-3 A. Small portable devices can > easily draw less than 10^-3 W nowadays.
Good point. The driver currently exports non-integer values, which is not acceptable, so indeed it needs to be changed. We want at least a resolution of 10^-3 W. Not sure about 10^-6 W. I am surprised that portable devices can really draw less than 1 mW, and be it the case, I doubt that manufacturers will embed a wattmetter: it would probably draw more current than the rest of the device ;) so it may not be relevant for our decision.
So I think I'd go with 10^-3 W, but I welcome diverging opinions. Out of curiosity, what is the physical resolution of IBM's device?
I see that the driver relies on IPMI. Can't it be merged with the out-of-tree impisensors driver then? This would give that driver some momentum so that it can finally be merged, and I would like to avoid having two drivers if one is enough. Note though that I don't know anything about IPMI so I might as well be totally wrong ;)
-- Jean Delvare - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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