GVFS blocks multiple cameras of same brand, even when model differs
At some point, it appears GVFS began to enforce a rule that says only one device with the same serial number is allowed, giving the message akin to the following:
gvfs-gphoto2-vo[1746]: device /dev/bus/usb/005/011 has an identical ID_SERIAL value to an existing device. Multiple devices are not supported.
This is a problem because for some (all?) Canon DSLRs, the kernel assigns the value Canon_Inc._Canon_Digital_Camera to ID_SERIAL. It seems to occur regardless of model. I have access to only two Canon DSLRs myself (very different models), but that's what I'm seeing.
Effectively that means when GIO/GVFS is running, the 2nd camera is rejected. To the desktop user it appears as if nothing happened when they insert it. Any program that uses libgphoto2 cannot see it either.
The primary libgphoto2 developer let me know that this ID_SERIAL assignment is happening at the kernel level, not the libgphoto2 driver. He says it needs to be fixed at the kernel or in GVFS.
I've also confirmed that in an older version of GVFS (Ubuntu 16.04) accepted multiple cameras of the same brand.
I imagine this behavior could be a real problem for people who run things like camera traps in which one device controls multiple cameras.
Thank you.