# AMD 7840 Fan and Temp issue (negative temp, fan is not starting)

**URL:** <https://community.frame.work/t/amd-7840-fan-and-temp-issue-negative-temp-fan-is-not-starting/72337>\
**Category:** Linux\
**Tags:** fedora\
**Created:** [July 18, 2025, 5:59pm UTC](https://community.frame.work/t/amd-7840-fan-and-temp-issue-negative-temp-fan-is-not-starting/72337 "2025-07-18T17:59:06Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![George\_T](https://avatars.discourse-cdn.com/v4/letter/g/d78d45/32.png) [@George\_T](https://community.frame.work/u/George_T)\
**Post date:** [July 18, 2025, 5:59pm UTC](https://community.frame.work/t/amd-7840-fan-and-temp-issue-negative-temp-fan-is-not-starting/72337/1 "2025-07-18T17:59:06Z")

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Which Linux distro are you using?  
Fedora Linux 42 (Workstation Edition) x86\_64

Which release version?  
updated July 18 2025

Which kernel are you using?  
Linux 6.15.6-200.fc42.x86\_64

Which BIOS version are you using?  
3.09 (latest available)

Which Framework Laptop 13 model are you using?  
AMD Ryzen 7 7840U

Hello,

I’m experiencing unusual behavior with my FW13 AMD 7840. Specifically, I’m observing negative temperature readings, and the fans are not engaging under load. However, manual fan control (via `ectool` and `fw-fanctrl`) appears to be functioning correctly.

I’ve already attempted to update Fedora and toggle the automatic fan management settings, but the issue persists.

k10temp sensor under load going up to 92 Celsius. No fan.

❯ acpi -t  
Thermal 0: ok, -17.2 degrees C  
Thermal 1: ok, 0.0 degrees C  
Thermal 2: ok, -17.2 degrees C  
Thermal 3: ok, -17.2 degrees C

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<div class="post-metadata">

**Author:** ![George\_T](https://avatars.discourse-cdn.com/v4/letter/g/d78d45/32.png) [@George\_T](https://community.frame.work/u/George_T)\
**Post date:** [July 21, 2025, 11:00am UTC](https://community.frame.work/t/amd-7840-fan-and-temp-issue-negative-temp-fan-is-not-starting/72337/2 "2025-07-21T11:00:41Z")

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I found a workaround using `fw-fanctl`.  
By changing the temperature reading module to use the k10temp AMD sensor, I’ve made the laptop usable.  
The modified module is `src/fw_fanctrl/hardwareController/EctoolHardwareController.py`

Function:

```auto
    def get_temperature(self):
        # Priority: k10temp -> EC sensors -> fallback

        # k10temp
        try:
            with open('/sys/class/hwmon/hwmon8/temp1_input', 'r') as f:
                temp_millidegrees = int(f.read().strip())
                temp_celsius = temp_millidegrees / 1000.0
                return float(round(temp_celsius, 2))
        except:
            pass

        # EC Sensors
        if self.noBatterySensorMode:
            raw_out = "".join(
                [
                    subprocess.run(
                        "ectool temps " + x,
                        stdout=subprocess.PIPE,
                        shell=True,
                        text=True,
                    ).stdout
                    for x in self.nonBatterySensors
                ]
            )
        else:
            raw_out = subprocess.run(
                "ectool temps all",
                stdout=subprocess.PIPE,
                shell=True,
                text=True,
            ).stdout

        raw_temps = re.findall(r"\(= (\d+) C\)", raw_out)
        temps = sorted([x for x in [int(x) for x in raw_temps] if x > 0], reverse=True)

        # safety fallback
        if len(temps) == 0:
            return 50
        return float(round(temps[0], 2))

```

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<div class="post-metadata">

**Author:** ![George\_T](https://avatars.discourse-cdn.com/v4/letter/g/d78d45/32.png) [@George\_T](https://community.frame.work/u/George_T)\
**Post date:** [September 21, 2025, 8:52pm UTC](https://community.frame.work/t/amd-7840-fan-and-temp-issue-negative-temp-fan-is-not-starting/72337/3 "2025-09-21T20:52:25Z")

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Found the solution for my case.

> [@Temp sensors on Framework 13 7040 series report negative temps](https://community.frame.work/t/temp-sensors-on-framework-13-7040-series-report-negative-temps/67454/9):
>
> This kinda sounds weird, but I found a solution for my negative temp sensors in not a so obvious way. Long story short – I tried to replace EVERYTHYNG screw-by screw, and sensors fixed after replacement of … O\_o … web-camera cable. Cable produced by EST (from the new cnc cover) - negative temp sensors. Cable produced by DX (from the original cover) - good state sensors.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex001/uploads/framework3/original/1X/64c81a89f963ddb07633887baceb642a4b056046.png) [@system](https://community.frame.work/u/system)\
**Post date:** [March 20, 2026, 8:53pm UTC](https://community.frame.work/t/amd-7840-fan-and-temp-issue-negative-temp-fan-is-not-starting/72337/4 "2026-03-20T20:53:11Z")

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Closed on March 20, 2026, 8:53pm UTC

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