[S] Change in coreboot[master]: mb/asrock/b75pro3-m: Drop CPU-fan tacho propertry

[Fabian Groffen (Code Review)]

Attention is currently required from: Felix Singer, Paul Menzel, Felix Held.

Fabian Groffen has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/73813 )

Change subject: mb/asrock/b75pro3-m: Drop CPU-fan tacho propertry
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Patch Set 7:

(1 comment)

Patchset:

PS4:
> Could you explain that more? […]

I've undone the original changes, which this comment referred to, so the problem no longer exists.

I've got two b75pro3-m boards, one that I can easily experiment with (it runs nothing), the other which is more of a server.  On both I flashed my changes and noticed that after a shutdown there was no way anymore to get the board powered on, except for shorting the pins on the ATX connector to force power.  While vendor firmware had the same problem, I could release the shorted pins after it started, but using coreboot as soon as the pins were released, the board would drop power.  This obviously was pretty crappy.

I believe the reason is because I modified the GPIO pins trying to get the CPUFANIN readings, as well as trying to apply settings vendor firmware did.  While doing so, I probably messed up some GPIO setting which prevented the nuvoton to short the power pins or something.  This setting was pretty much permanent until the CMOS battery was removed and fully cleared for a good while.  Because I didn't realise at first, I re-applied the problem using a coreboot boot after such clear, but when it dawned on me I was messing with things I probably shouldn't, and used the settings from h77pro4-m instead, a CMOS clear allowed me to shut down and boot again using a simple power button short.

All I wanted to achieve is to get the CPUFAN RPM readings and be able to control the fan speed, which I now have thanks to the h77pro4-m settings.  It also resolves the warnings/errors seen during coreboot boot, so I think I should really leave it at this, as I had ~2d of quite nervous operation on the one board which serves as server.  :)