Re: [PATCH v2] hwmon: Driver for temperature sensors on SATA drives

[Gabriel C <nix.or.die@gmail.com>]

Am So., 12. Jan. 2020 um 16:26 Uhr schrieb Guenter Roeck <linux@roeck-us.net>:
>
> On 1/12/20 5:45 AM, Gabriel C wrote:
> > Am So., 12. Jan. 2020 um 14:07 Uhr schrieb Guenter Roeck <linux@roeck-us.net>:
> >>
> >> On 1/12/20 4:07 AM, Linus Walleij wrote:
> >>> On Sun, Jan 12, 2020 at 1:03 PM Gabriel C <nix.or.die@gmail.com> wrote:
> >>>> Am So., 12. Jan. 2020 um 12:22 Uhr schrieb Linus Walleij
> >>>> <linus.walleij@linaro.org>:
> >>>>>
> >>>>> On Sun, Jan 12, 2020 at 12:18 PM Gabriel C <nix.or.die@gmail.com> wrote:
> >>>>>
> >>>>>> What I've noticed however is the nvme temperature low/high values on
> >>>>>> the Sensors X are strange here.
> >>>>> (...)
> >>>>>> Sensor 1:     +27.9°C  (low  = -273.1°C, high = +65261.8°C)
> >>>>>> Sensor 2:     +29.9°C  (low  = -273.1°C, high = +65261.8°C)
> >>>>> (...)
> >>>>>> Sensor 1:     +23.9°C  (low  = -273.1°C, high = +65261.8°C)
> >>>>>> Sensor 2:     +25.9°C  (low  = -273.1°C, high = +65261.8°C)
> >>>>>
> >>>>> That doesn't look strange to me. It seems like reasonable defaults
> >>>>> from the firmware if either it doesn't really log the min/max temperatures
> >>>>> or hasn't been through a cycle of updating these yet. Just set both
> >>>>> to absolute min/max temperatures possible.
> >>>>
> >>>> Ok I'll check that.
> >>>>
> >>>> Do you mean by setting the temperatures to use a lmsensors config?
> >>>> Or is there a way to set these with a nvme command?
> >>>
> >>> Not that I know of.
> >>>
> >>> The min/max are the minumum and maximum temperatures the
> >>> device has experienced during this power-on cycle.
> >>>
> >>
> >> No, that would be lowest/highest. The above are (or should be) per-sensor
> >> setpoints. The default for those is typically the absolute minimum /
> >> maximum of the supported range.
> >>
> >> Some SATA drives report the lowest/highest temperatures experienced
> >> since power cycle, like here.
> >>
> >> drivetemp-scsi-5-0
> >> Adapter: SCSI adapter
> >> temp1:        +23.0°C  (low  =  +0.0°C, high = +60.0°C)
> >>                          (crit low = -41.0°C, crit = +85.0°C)
> >>                          (lowest = +20.0°C, highest = +31.0°C)
> >>
> >
> > The SATA temperatures are fine and reported like this here too, just
> > the nvme ones are strange.
> >
> > drivetemp-scsi-4-0
> > Adapter: SCSI adapter
> > temp1:        +28.0°C  (low  =  +1.0°C, high = +61.0°C)
> >                        (crit low =  +2.0°C, crit = +60.0°C)
> >                        (lowest = +16.0°C, highest = +31.0°C)
> >
> > drivetemp-scsi-12-0
> > Adapter: SCSI adapter
> > temp1:        +29.0°C  (low  =  +1.0°C, high = +61.0°C)
> >                        (crit low =  +2.0°C, crit = +60.0°C)
> >                        (lowest = +18.0°C, highest = +32.0°C)
> >
> > and so on.
> >
> > Btw, where I can find the code does these calculations?
> >
>
> Not sure if that is what you are looking for, but the nvme hardware
> monitoring driver is at drivers/nvme/host/hwmon.c, the SATA hardware
> monitoring driver is at drivers/hwmon/drivetemp.c.
>

I have a look thanks.

I'm using your v2 patch for the nvme part since you posted it on 5.4 kernels.
This is probably why I find the way the temperatures are now reported
very strange.

The ADATA XPG SX8200 Pro in my laptop seems to work better:

nvme-pci-0200
Adapter: PCI adapter
Composite:    +37.9°C  (low  =  -0.1°C, high = +74.8°C)
                      (crit = +79.8°C)

Low is 0° which is what the spec suggests.

> The limits on nvme drives are configurable.

Yes, I found this out already.

> root@server:/sys/class/hwmon# sensors nvme-pci-0100
> nvme-pci-0100
> Adapter: PCI adapter
> Composite:    +40.9°C  (low  = -273.1°C, high = +84.8°C)
>                         (crit = +84.8°C)
> Sensor 1:     +40.9°C  (low  = -273.1°C, high = +65261.8°C)
> Sensor 2:     +43.9°C  (low  = -273.1°C, high = +65261.8°C)
>
> root@server:/sys/class/hwmon# echo 0 > hwmon1/temp2_min
> root@server:/sys/class/hwmon# echo 100000 > hwmon1/temp2_max

An lm-sensors configuration will work too.

> root@server:/sys/class/hwmon# sensors nvme-pci-0100
> nvme-pci-0100
> Adapter: PCI adapter
> Composite:    +38.9°C  (low  = -273.1°C, high = +84.8°C)
>                         (crit = +84.8°C)
> Sensor 1:     +38.9°C  (low  =  -0.1°C, high = +99.8°C)
> Sensor 2:     +42.9°C  (low  = -273.1°C, high = +65261.8°C)
>
> If you dislike the defaults, just configure whatever you think is
> appropriate for your system.

It's not about disliking the values. I want to find out if these Samsung models
don't support that, or it is a bug somewhere in writing/calculating the values.

In the case, Samsung and others don't support such a thing wouldn't be
better to just ignore
the bogus reading altogether?