struct stream_buffer {
	 struct v4l2_buffer vidbuf; /* For the V4L ioctl's */
	 int fields_grabbed; /* Two-bit pair of flags indicating which fields
				have been grabbed (i.e., 00 = no fields,
				11 = both) */
	 struct list_head node; /* Connection into queues */
	 int requested; /* Set by REQBUF ioctl */
	 unsigned char *vaddress; /* This is the pointer to the vmalloc()'d
				     memory into which the actual frame goes */
	 int vma_refcount; /* Reference count */
};


/********************************************************************/
/**
 * struct stream_buffer_queue - FIFO of stream_buffer structs
 */
struct stream_buffer_queue {
	 struct stream_buffer *streambuf; /* Pointer to node data */
	 struct list_head head; /* Start of the queue */
	 rwlock_t lock; /* Lock to protect the queue */
	 int length; /* How many nodes are on the queue */
};


/********************************************************************/
/**
 * HRT device descriptor
 */
typedef struct {
	 /* Added By Ryan Walega & Daniel Beech */
	 int 			 registered;
	 int                     num;
	 int                     state;
	 /* minor device number, index in hrt_devices[] */
	 unsigned long           virt_addr;
	 unsigned long           phys_addr;
	 /* cannot be opened again until released */

	 /* spinlock and is_locked control access to the device */
	 spinlock_t              spinlock;
	 int                     is_locked;
	 wait_queue_head_t       wait_queue;
	 struct timer_list       timer;
	 struct tasklet_struct   tasklet;
	 int                     timer_active;
	 int                     tasklet_active;
	 /* timer_active != 0 iff timer or irq is active */
	 int                     irq;
	 /* irq != 0 if board supports interrupts
	    = -irq if handler not installed
	    = irq if handler is installed */
	 volatile
	 int                     irq_count;
	 volatile
	 int                     i2c_bits;
	 /* last values written to i2c */
	 char                    saa7110_registers[HRT_SAA7110_MAXREG+1];
	 /* video data format, and dependent values */
	 int                     mode;
	 int                     rows, cols, bytes_per_pixel;
         int                     win_row, win_col, win_width, win_height;
	 /* current field being digitized */
	 int                     field;
	 /* how many field changes we are waiting for */
	 int                     field_changes;
	 /* the device is either frozen or being frozen */
	 int                     is_frozen;
	
	 /* Local buffer for storing the frame currently read from the device */
	 /* Added june 8,2005 - atulya/sean */
	 unsigned char *framedata;
	 /* Variable to keep track of the field being read inside the current frame */
	 unsigned int field_id;
	 /* Semaphore for the device structure */
	 struct semaphore sem;
	 /* Local buffer used for manipulation of the data returned 
	  * by the color device.
	  * ONLY used by the color device
	  */
	 unsigned char *localbuf;
	 /* Flag for streaming mode */
	 int streaming;
	 /* Number of buffers for streaming */ 
	 int numbufs; 
	 /* Array of buffers */
	 struct stream_buffer *streambufs; 
	 /* List of queued buffers */
	 struct stream_buffer_queue capture_list; 
	 /* List of filled buffers */
	 struct stream_buffer_queue done_list; 
	 int stream_buffers_mapped;
	 struct stream_buffer stream_buf[MAX_CAPTURE_BUFFERS];
	 int stream_buffers_requested;

	 /* Variable used to keep track of our state while streaming 
	  * added 13 June 2005 - Atulya/Sean
	  */
	 int streaming_state;
	
	 /* We allow the user to make the view upside down too !
	  * came out of compulsion actually since we have the cameras installed
	  * upside down !
          * the following variable determines what sort of output we return to the user
	  * set using an ioctl
	  */
	 int upside_down;	

	 /* Following structure used for registering with V4L */
	 struct video_device video_dev; 
	 struct v4l2_format clientfmt;
	 struct v4l2_captureparm capture;
	 
	 /* Bytes per raster line. 640 for grey scale card
	  * and 2*640 = 1280 for the color card
	  */
	 unsigned int bytesperline; 
	 /* Memory size of the entire frame
	  * = 512 X 480 X 1 bytes per pixel= 240 KB for grey scale card
	  * = 640 X 480 X 2 bytes per pixel= 600 KB for color card
	  */
	 unsigned int framesize;
	 /* Current region of interest 
	  * fields = width,height,starty,startx
	  */
	 struct subwindow *win; 

#ifdef CONFIG_PCI
	 /* structure to represent a pci device */
	 struct pci_dev          *pci_dev;
#endif
} hrt_t;