Re-recognizing an internal SD card reader

Last week I accidentally hit the "Safely Remove Drive" option instead of the "Eject Disk" option for my internal SD card reader in Ubuntu. After doing this, I could not get the computer to show the card reader, even after following forum advice to unload and reload modules and at last resorting to a reboot.
I recently picked up a cheap used usb video-in device, and when trying to get it to work in Ubuntu I tried running lsusb to find out if the device was recognized. lsusb took a long time to run, and when I checked dmesg I saw a number of errors of the form

device descriptor read/64, error -110

Searching on Google turned up this page, where users reported that shutting down and unplugging the system fixed their problem. I gave it a try, and sure enough it worked. I'm posting this because I didn't see anyone suggest this fix for the problem caused by using "Safely Remove Drive". Hopefully someone else with the same problem can find the solution here.

Segfault write-up

I finally got around to documenting some info about my homemade balancing scooter. See here.