Porting OpenBSD's sysctl hw.sensors framework to FreeBSD

[Poul-Henning Kamp]

In message <20070711104247.P58526 at fledge.watson.org>, Robert Watson writes:
>On Wed, 11 Jul 2007, Poul-Henning Kamp wrote:

>It seems clear that people would like all these measurements to be available, 
>even if not by the precise mechanism proposed.  So far the specific technical 
>criticals have been:
>
>- There's such a diversity of motherboard devices and probe mechanisms that
>   any kernel driver would become rapidly over-burdened and needlessly
>   complicated.

Not to mention size.

Anything that sensibly can be done from userland should be done in userland.

>This doesn't argue for doing nothing, just that perhaps a kernel device driver 
>is the wrong place.

100% agreement here.

I would prefer to see the kernel drivers only offer transport and have all the
MIB stuff happen in userland.

In other words, I think the right way to think about this is: "Assume
the existence of sensord(8), design client (sensors) and server
(apps that want to know what the sensors show) APIs"

Another thing to remember is that not all sensors relating to a system lives
inside the system.  Voltage, Fire, Temperature and other relevant sensors may
need network or serial port communication instead if i2c or IPMI, but that
doesn't mean that it shouldn't be possible to integrate it in the sensor
MIB.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.