extern ssize_t drm_read(struct file *filp, char __user *buffer,
size_t count, loff_t *offset);
extern int drm_release(struct inode *inode, struct file *filp);
extern ssize_t drm_read(struct file *filp, char __user *buffer,
size_t count, loff_t *offset);
extern int drm_release(struct inode *inode, struct file *filp);