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Patrick Tully Steven Bronson. USB Card Scanner Driver. Motivation. Monitors in Majors Lab scan FSU cards using a USB card reader USB card reader generates keystrokes Program must have focus at all times, in the correct textbox. Pre-existing Projects. Read from /dev/usb/hiddev
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Patrick Tully Steven Bronson USB Card Scanner Driver
Motivation • Monitors in Majors Lab scan FSU cards using a USB card reader • USB card reader generates keystrokes • Program must have focus at all times, in the correct textbox
Pre-existing Projects • Read from /dev/usb/hiddev • Only works for the USB HID card scanner • Write a userspace program using libusb or PyUSB • Requires root privileges each time • Depends on deprecated (obsolete?) usbfs
Contribution • Used a small part (boilerplate) of the usbkbd driver as a starting point. • Most of the work went into implementing read, which did not exist in usbkbd. • Create /dev/cardscanner that can be opened and read.
Challenges • USB probe order • Determined by module insertion order • Fixed with USB quirks • Kernel circular buffer implementation is not really • Record API makes more sense, but Unix loves byte streams (why pass records when you can design ambiguous grammars?)