libusb
libusb_init() fails with Other error [-99] if in chroot and --disable-udev
I am getting:
Failed to get USB context: failed to init libusb: Other error [-99] (g-usb-context-error-quark, 0)
When running in chroot where /dev/bus/usb is empty. Apparently no error is given if udev is being used.
I would like to clarify if libusb_init is expected to succeed even if no USB bus is present. And to have consistent behavior regardless of if using --disable-udev or --enable-udev.
For background, see: https://github.com/hughsie/fwupd/issues/1219
Why was this bug report closed? I'm here two years later, trying to figure out why I am getting "Fu-WARNING **: FuMain: failed to get USB context: failed to init libusb: Other error [-99]" errors and there is ZERO information here about this libusb bug or its resolution. I have non-USB devices requiring firmware updates to work correctly and libusb is a showstopper for me. "Use the mailing list" is absolutely useless resolution information.
Good point. Apparently this ticket was closed wrongly (Edit to add: without properly mentioning the reasoning).
Whether this is an issue that is another story.
Personally I did not think it is an issue at the time. And I still think it is not a real issue for libusb now. If there is no USB controller present, I think there is nothing wrong for libusb to fail libusb_init.
But I will let other libusb admins and contributors to chime in for their opinions.
Please also refer to past issue #511.
When the container does not support libudev (--disable-udev) and Netlink, libusb_init() will fail.
For that ticket, we improved the codes but it will not change that libusb_init will fail in that situation. https://github.com/libusb/libusb/commit/a5624b22267ec0e146825d3fe94d9e4b2f5ae503
@fuzzyeric And also I do not understand why this becomes a showstopper for you in fwupd since you are using non-USB device and that libusb_init failing is just an warning for the application. I assume it has other codes to deal with non USB devices.
On the other hand, there is a potential useful enhancement to libusb here. But the author has closed the pull-request. Maybe you can take a look whether it is useful info or not. https://github.com/libusb/libusb/pull/559
It mentioned the following. https://community.intel.com/t5/Intel-Distribution-of-OpenVINO/NCS2-in-docker-container-on-RPI-results-in-RuntimeError-Can-not/m-p/1191905/highlight/true#M19803
IMHO even if we don't document it I expect libusb_init may fail if no USB bus exists. This is not a libusb bug.
One the issue raised in https://github.com/fwupd/fwupd/issues/1219 is that libusb_init() error codes are not well documented.