No more interrupt loops

9 April 2026

I used to have severe problems installing and running Linux Mint on an HP Pavilion laptop, due to an endless loop of interrupts. Later on I had similar problems, though not nearly as severe, using Bunsenlabs Boron on a Clevo laptop bought from Dutch vendor BTO.

Meanwhile on both machines I have changed the OS to Debian Forky (a.k.a. Testing), with Fluxbox as a superlight and simple Desktop Environment (without the desktop, which I do not need). And the interrupt loops are gone! I suspect something was done in the Linux kernel to solve it. But I’m not sure.

In both cases, uname -a reports 6.19.10+deb14-amd64 as the Linux kernel version.

From dmidecode I get this information, for the HP:

HP: SMBIOS 2.8 present
Platform Firmware Information
	Vendor: Insyde
	Version: F.21
	Release Date: 06/13/2017
	Platform Firmware Revision: 15.33
	Embedded Controller Firmware Revision: 84.51

And for the Clevo (BTO):

BTO: SMBIOS 3.2.0 present
Platform Firmware Information
	Vendor: INSYDE Corp.
	Version: 1.07.13
	Release Date: 10/27/2020
	Platform Firmware Revision: 7.13
	Embedded Controller Firmware Revision: 7.5

As you can imagine, I am quite pleased with this.

Correction, the loop is back!

12–15 April 2026

On the HP Pavilion, the endless interrupt loop, consuming around 45% of 1 of 4 hardware / hyper-threading cores of the i3-6100U processor, is back. Didn’t I properly check it then?

Instead of irq/123-aerdrv, command top now shows irq/124-aerdrv. Small and probably unimportant difference. The command
grep '124:' /proc/interrupts
results in:
124: 0 1 0 0 IR-PCI-MSI-0000:00:1c.3 0-edge aerdrv, PCIe bwctrl
where bwctrl means ‘bandwidth control’. Something to do with Wi-Fi?

Luckily, I had timeshift create snapshots, which I can restore at will, and try out. And indeed two snapshots back, the loop was not there. So what is the difference, or what are the differences, that might cause this behaviour?

Found it: from a snapshot where I had no systray utilities installed yet, once I installed nm-tray, the looping started again. And from a snapshot with five systray utilities installed, after I removed nm-tray and network-manager and rebooted, the loop was gone. So the problem is probably in a malfunctioning Wi-Fi adapter.

I had problems with that before, concerning the antenna selection. The adapter is a Realtek rtl8723be. In the past, I could make it work by changing the default antenna setting, which produced an extremely weak signal, to a setting 1 or 2, as follows:

# Remove the module from the kernel:
sudo modprobe -rv rtl8723be
# Insert the module into the kernel, using that antenna setting:
sudo modprobe -v rtl8723be ant_sel=1
# Bring the network adapter up:
sudo ip link set wlp2s0 up
# Look what has changed:
ip addr

Now that I tried it again, it failed. The Wi-Fi remained down. After the insert or after upping, I noticed that the interrupt loop returned. After removing it, the loop vanished.

I’ve given up and I’ll leave it at that. It’s not a big problem, because I bought this HP laptop on 2 July 2016, almost ten years ago, it is now a back-up for a back-up, in case I really have no other working computer left. Some other components are broken too. The cooling fan makes funny noises, as if the bearings are worn, my attempts to remove and replace it failed, and in the process I didn’t manage to reconnect the touchpad. But I can connect a USB mouse. And everything else still works, including the ethernet connection. And the screen has beautiful, warm colours.