[lm-sensors] [PATCH] hwmon: (adt7475) Fix temperature fault flags

Jean Delvare khali at linux-fr.org
Sun Nov 15 17:54:52 CET 2009


On Mon, 9 Nov 2009 13:26:21 +0100, Jean Delvare wrote:
> Hi Hans,
> 
> On Mon, 09 Nov 2009 11:51:54 +0100, Hans de Goede wrote:
> > I've a adt7475 on my home development machine in the Netherlands
> > (I'm currently in Brno).
> > 
> > I can (and would like to) verify this fix when I'm back home (friday).
> > The adt7475 on my machine is used to control an additional fan, and has
> > no external temperature sensors connected (AFAIK).
> > 
> > I've tested the original adt7475 driver on this machine, but I may
> > have simply out "temp1 ignore" (and temp3) in my sensors.conf missing
> > this.
> 
> Thanks for the feedback. I have tested on 3 dumps I have here, one
> ADT7475 and two ADT7473. The ADT7475 reports -64°C for temp1 and temp3
> and has both fault bits set to 1. The two ADT7473 reports reasonable
> values for both temp1 and temp3 and have the fault bits set to 0.
> Assuming that the ADT7473 and ADT7475 are almost the same chip and
> should thus behave the same, my change would be correct.
> 
> I have also noticed that Jordan's original code did not have the
> inversion:
> 
> http://lists.lm-sensors.org/pipermail/lm-sensors/2008-January/022338.html
> 
> 	case FAULT:
> 		/* Note - only for remote1 and remote2 */
> 
> 		ret = sprintf(buf, "%d\n",
> 			(data->alarms & (sattr->index ? 0x4000 : 0x8000)));
> 		break;
> 
> but it lacked normalization (output value 0x4000 or 0x8000 instead of
> 1.) Maybe when normalizing the logic was inverted by accident?
> 
> The few ADT7475 data points I have found on the web suggest that on
> many boards temp1 and temp3 are not connected. This could explain why
> the bug went unnoticed so far. Why vendors use these chips, which are
> specifically designed for automatic temperature-based fan speed
> control, in designs where they don't bother wiring the thermal sensors,
> is beyond me.
> 
> Anyway, I will wait for you to return home and test on your system,
> before sending the patch to Linus.

Hans, did you have the time to test this patch?

-- 
Jean Delvare




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