I have a Canon 40D that worked well with 32-bit Ubuntu all the way from 10.04 through 12.04. However, I switched to 64-bit 12.04 a while back, and since then, connecting the camera just brings up a simple dialog:

Unable to mount Canon Digital Camera

Error initializing camera: -1: Unspecified error

This problem persists in 12.10 and the latest 13.04 build.

syslog doesn't say much other than

kernel: [12089.871412] usb 3-1: new high-speed USB device number 3 using xhci_hcd

mtp-probe: checking bus 3, device 3: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1"

mtp-probe: bus: 3, device: 3 was not an MTP device

kernel: [12453.142322] usb 3-1: USB disconnect, device number 3

I've seen some random bugs on launchpad about this, but nothing that directly pertains to it. This seems like such a glaring problem that I figure I'm doing something wrong on my end. What's the proper way to get a camera to work on 64-bit Ubuntu?