Re: adt7460 temperature target

I have a PowerMac6,4 (eMac) and noticed its fan starts to run as soon as th=
e machine is powered up and it keeps running as long as it stays powered
on.

I'm not fluent in openfirmware but fussing there, I had an impression that =
there could be a way there...

Alternatively, maybe in Jon's machine case it's worth to check the followin=
g project:
https://github.com/andreafabrizi/G4FanControl

Cheers.

Le samedi 25 novembre 2023 =C3=A0 08:57 -0700, Theo de Raadt a =C3=A9crit=
=C2=A0:
> For the temperature sensing drivers we have *intentionally* avoided doing
> writes to i2c devices.
>=20
> On many machines, ACPI/SMI retain control of these devices, and make
> changes behind OpenBSD's back without us knowing what is going on.=C2=A0 =
We
> don't know if this will break a machine, do to their changes depending
> up on a specific configuration.=C2=A0 The breakage could be subtle and ve=
ry
> weird.=C2=A0 This is a policy we established for all these drivers, and w=
e've
> avoided creating too many exceptions to it because if the exception
> becomes the rule, subtle interactions could create harm.
>=20
> As a result, all sensor drivers for these chips only do 'sensing',
> meaning they only do reads.=C2=A0 (OK, a few drivers do writes to "enable=
"
> them, if we discover that the system has not yet enabled them, then it
> means there is no BIOS driving behind our back; this situation feels
> more safe, then OpenBSD is in control).
>=20
> That said, your argument is for macppc.=C2=A0 I would not argue against a
> macppc-only configuration change, especially if it is clearly from a
> "chip not configured state"), but I don't know what that code would look
> like, whether it is an #ifdef or run-time comparison of the machine
> architecture and model.
>=20
> [email protected]=C2=A0wrote:
>=20
> > Hello. It's been about 6 months since I tweaked adt(4) to control
> > the temperature target that the cooling system uses to regulate
> > itself, following the source code of G4FanControl which may be found
> > around online.
> >=20
> > This makes it possible to power the fans on earlier and thus improve
> > thermals and, hopefully, lifespan of the system which -given these
> > macppc machines are quite old and increasingly rare- I would argue
> > is worth preserving. I myself find it quite comfortable at 46 degC
> >=20
> > Perhaps it would be better to add a sysctl to control the temperature
> > target? This diff is a fully functional proof of concept I guess,
> > would really appreciate your thoughts.
> >=20
> > All the best
> >=20
> > Index: dev/i2c/adt7460.c
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > RCS file: /cvs/src/sys/dev/i2c/adt7460.c,v
> > retrieving revision 1.22
> > diff -u -p -r1.22 adt7460.c
> > --- dev/i2c/adt7460.c=C2=A0=C2=A0=C2=A06 Apr 2022 18:59:28 -0000=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A01.22
> > +++ dev/i2c/adt7460.c=C2=A0=C2=A0=C2=A023 Nov 2023 16:23:48 -0000
> > @@ -34,6 +34,9 @@
> > =C2=A0#define ADT7460_REM1_TEMP=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A00x25
> > =C2=A0#define ADT7460_LOCAL_TEMP=C2=A0=C2=A0=C2=A0=C2=A0=C2=A00x26
> > =C2=A0#define ADT7460_REM2_TEMP=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A00x27
> > +#define ADT7460_REM1_TEMP_TRG=C2=A0=C2=A00x68
> > +#define ADT7460_LOCAL_TEMP_TRG=C2=A00x67
> > +#define ADT7460_REM2_TEMP_TRG=C2=A0=C2=A00x69
> > =C2=A0#define ADT7460_TACH1L=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A00x28
> > =C2=A0#define ADT7460_TACH1H=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A00x29
> > =C2=A0#define ADT7460_TACH2L=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A00x2a
> > @@ -193,6 +196,16 @@ adt_attach(struct device *parent, struct
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 sc->sc_addr, &cmd, sizeof cmd=
, &data, sizeof data, 0)) {
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
iic_release_bus(sc->sc_tag, 0);
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
printf(": cannot set control register\n");
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return=
;
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0}
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > +
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0for (cmd =3D ADT7460_LOCAL_T=
EMP_TRG; cmd <=3D ADT7460_REM2_TEMP_TRG; cmd++){
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0data =3D 46; /* temperature target in deg C*/
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0if (iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 sc->sc_addr, &cmd, sizeof cmd, &dat=
a, sizeof data, 0)) {
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0iic_re=
lease_bus(sc->sc_tag, 0);
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0printf=
(": cannot set temperature target register\n");
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
return;
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> >=20
>=20