Bug 2079041

Summary:	Raspberry Pi 4b case-fan/gpio-fan control: hysteresis not working in f36 IoT
Product:	[Fedora] Fedora	Reporter:	Armin Warda <armin.warda>
Component:	bcm283x-firmware	Assignee:	Peter Robinson <pbrobinson>
Status:	CLOSED DUPLICATE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	36	CC:	laura, pbrobinson, pwhalen
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Target Release:	---
Hardware:	aarch64
OS:	Linux
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Fixed In Version:		Doc Type:	If docs needed, set a value
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Last Closed:	2022-04-27 00:34:26 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Armin Warda 2022-04-26 18:36:56 UTC

Fedora-IoT-36-20220405.0.aarch64.raw.xz
Fedora-IoT-36-20220411.0.aarch64.raw.xz
Fedora-IoT-36-20220413.0.aarch64.raw.xz 
Fedora-IoT-36-20220426.0.aarch64.raw.xz 

/boot/efi/config.txt:
dtoverlay=gpio-fan,gpiopin=14,temp=80000

Raspberry Pi 4b case-fan/gpio-fan control with dtoverlay is working, 
fan is triggered on at temp>80°C, but
HYSTERESIS 70<80°C not working: 
fan is flipping on/off around ~80°C,
fan should NOT be triggered off before temp falls below 70°C!

To compare, I booted Raspian OS:
2022-04-04-raspios-bullseye-arm64-lite.img.xz (Kernel 5.15.32-v8+ aarch64)

/boot/config.txt:
dtoverlay=gpio-fan,gpiopin=14,temp=80000

and here the hysteresis _is_ working as expected:

temp>80°C => case-fan/gpio-fan is switched on
temp<70°C => case-fan/gpio-fan is switched off

If the temp is between 70 and 80°C, the fan is not triggered on/off!

See also https://bugzilla.redhat.com/show_bug.cgi?id=2047329 which was originally reported for Fedora 35, where gpio-fan control did not work at all.

Comment 1 Peter Robinson 2022-04-27 00:34:26 UTC

Having multiple bugs for the same problem is likely not overly useful. Duping to the other bug as there's more info there.

*** This bug has been marked as a duplicate of bug 2047329 ***