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Commit 92918a53 authored by Hans de Goede's avatar Hans de Goede Committed by Mauro Carvalho Chehab
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V4L/DVB (12075): gspca_ov519: check ov518 packet numbers 



Check ov518 packet numbers to detect dropped packets.

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 124cc9c0

drivers/media/video/gspca/ov519.c

+23 −6
Original line number Diff line number Diff line
@@ -50,6 +50,8 @@ static int i2c_detect_tries = 10; 
struct sd {

	struct gspca_dev gspca_dev;		/* !! must be the first item */



	__u8 packet_nr;



	char bridge;

#define BRIDGE_OV511		0

#define BRIDGE_OV511PLUS	1
@@ -2391,18 +2393,33 @@ static void ov518_pkt_scan(struct gspca_dev *gspca_dev, 
			__u8 *data,			/* isoc packet */

			int len)			/* iso packet length */

{

	PDEBUG(D_STREAM, "ov518_pkt_scan: %d bytes", len);



	if (len & 7) {

		len--;

		PDEBUG(D_STREAM, "packet number: %d\n", (int)data[len]);

	}

	struct sd *sd = (struct sd *) gspca_dev;



	/* A false positive here is likely, until OVT gives me

	 * the definitive SOF/EOF format */

	if ((!(data[0] | data[1] | data[2] | data[3] | data[5])) && data[6]) {

		gspca_frame_add(gspca_dev, LAST_PACKET, frame, data, 0);

		gspca_frame_add(gspca_dev, FIRST_PACKET, frame, data, 0);

		sd->packet_nr = 0;

	}



	if (gspca_dev->last_packet_type == DISCARD_PACKET)

		return;



	/* Does this device use packet numbers ? */

	if (len & 7) {

		len--;

		if (sd->packet_nr == data[len])

			sd->packet_nr++;

		/* The last few packets of the frame (which are all 0's

		   except that they may contain part of the footer), are

		   numbered 0 */

		else if (sd->packet_nr == 0 || data[len]) {

			PDEBUG(D_ERR, "Invalid packet nr: %d (expect: %d)",

				(int)data[len], (int)sd->packet_nr);

			gspca_dev->last_packet_type = DISCARD_PACKET;

			return;

		}

	}



	/* intermediate packet */