[lm-sensors] Not detecting all fan RPMs

Glenn Hollowell temp1 at blepsias.net
Mon Mar 26 22:33:59 CEST 2012

I'd assumed that since I am able to see correct RPMs for all fans while
in BIOS, I'd be able to parse out correct RPMs in Linux-OS as well. My
impression is also that correct RPMs are also displayed using the
Windows-OS application, "SpeedFan". 
Thanks again for your thoughts on this matter. gh

On Mon, 2012-03-26 at 22:28 +0200, Jean Delvare wrote:
> On Mon, 26 Mar 2012 13:16:35 -0700, Guenter Roeck wrote:
> > On Mon, 2012-03-26 at 15:44 -0400, Jean Delvare wrote:
> > > The NCT6775 supports only 4 fans, so either there is some multiplexing
> > > in place (which we don't support) or you have a second hardware
> > > monitoring chip on your system.
> >
> > I had not thought about multiplexing - good point. That would explain
> > why the chassis fans can only be configured for manual mode or full on.
> From a monitoring perspective, this makes absolutely no sense of
> course, as this means a delay in detecting fan failure. But the fact is
> that we've already seen this in the past. Manufacturer apparently
> preferred to save a few cents per board by using multiplexing and
> getting an ugly and unreliable solution rather than adding a second
> hardware monitoring chip for a clean and reliable one. Tsss...

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