int drm_agp_free (struct inode * inode, struct file * filp, unsigned int cmd, unsigned long arg);
\param inode device inode. \param filp file pointer. \param cmd command. \param arg pointer to a drm_agp_buffer structure. \return zero on success or a negative number on failure.
Verifies the AGP device is present and has been acquired and looks up the AGP memory entry. If the memory it's currently bound, unbind it via unbind_agp. Frees it via free_agp as well as the entry itself and unlinks from the doubly linked list it's inserted in.