Since my upgrade to Qubes 4.3, a lot of USB-related functionality is acting up. Most of it is too confusing to write good bug reports on. I hope there is a common denominator or something that changed between Qubes 4.2 and 4.3 that I may switch back.
The device icon is unreliable
Clicking on the qubes devices icon shows a list of devices.
Sometimes devices don’t show up, sometimes devices are not correctly marked as attached or attached to dead VMs. The qvm-device command usually reports the correct/expected devices.
One bug I could report, that didn’t show up again since then was a line of text that probably should only show up when no sys-usb is present yet.
Sometimes block devices appear only with their partitions, not the physical device (so e.g. sys-usb:sda is missing). This is sometimes replicated in qvm-block, sometimes the physical device is present there.
Attaching devices takes forever and mounting is slow
I use an external HDD and it worked fine in 4.2. It showed up as expected, was mountable as expected. It did experience hickups from time to time, which I suspect to be caused by a weak USB-port on my laptop. (notably power-spiky changes on my hardware would kick it out)
With Qubes 4.3, I experience completely different, but much more persistent/reproducible issues. Attaching the HDD may freeze most of the Qubes-GUI for minutes. I’m not sure what all affected components are, the device-icon and the qube-manager definitely freeze, opening new VM-windows works.
When the HDD finally is attached, mounting takes similarly forever. Accessing files on the drive is similarly slow. I’ve tried increasing sys-usb memory to 1GB, so far without detectable changes. (HDD is attached via USB 3.0, so I’m not expecting GB/s transfer rates, but it is extremely slow compared to Qubes 4.2)
Additional tidbit: When I watch a movie stored on the HDD, it stutters. Interestingly, the stutter seems to be the same no matter the bitrate/resolution/size of that movie. This makes me think there is some interrupting in the Qubes-Data-Transfer magic going on.
usb-devices can’t be attached, unless …
I use an external bluetooth antenna, specifically to use bluetooth headphones with sys-audio. I have an internal bluetooth device that behaves like a USB-device.
When I try to attach my external antenna to sys-audio after sleep, I wait for a bit and it fails. This is perfectly repeatable. Then I attach my internal bluetooth device to sys-audio and it works. Then I detach my internal and reattach my external bluetooth antenna and it works immediately.
This went away recently, probably because I am playing around with getting Si0x-sleep to work.
Doing anything with devices blocks my screen with notifications
Whenever I change something with my devices, I get my screen filled with notifications that sys-audio was blocked from doing something. I’m not sure if this is a policy-issue or part of the “something changed” complex in device handling. This is my lowest priority.
Conclusion
What changed? Is there a simple way to recreate the stability of 4.2 and wait for updates to the offending parts? Anything in particular I should analyze and report an issue on?