Greg Kroah-Hartman shared that with the staging driver patches for Linux 3.17, there's over 39,000 new lines of code while over 254,000 lines have been removed. The big code delta comes from 14 different drivers being removed that were "obsolete and no one was willing to work on cleaning them up."
The drivers removed with Linux 3.17 include Crystalhd, Winbond, wlags49_h2, serqt_usb2, dgrp, cxt1e1, tidspbridge, ced1401, frontier, keucr, phison,silicom, and sep. Of that list, the crystalhd driver may be noticeable for Broadcom's Crystal HD audio/video hardware coder.
Besides removing the old cruft, the staging pull has continued work on the staging Lustre driver, Unisys, gdm72xx, rtl8192u, rtl8188eu, BCM, Comedi, vt6655, and the other usual staging churn.
The full list of Linux 3.17 staging changes can be found via this pull request.