[media] gspca - sn9c20x: Fix loss of frame start

The frame header was checked on packets of size 64 bytes only, while the webcams
may put a frame header at the beginning of bigger packets.

Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/media/video/gspca/sn9c20x.c b/drivers/media/video/gspca/sn9c20x.c
index 9e198b45c3c8..e54bf54b3901 100644
--- a/drivers/media/video/gspca/sn9c20x.c
+++ b/drivers/media/video/gspca/sn9c20x.c
@@ -2457,7 +2457,7 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
         int avg_lum;
         static u8 frame_header[] =
                 {0xff, 0xff, 0x00, 0xc4, 0xc4, 0x96};
-        if (len == 64 && memcmp(data, frame_header, 6) == 0) {
+        if (len >= 64 && memcmp(data, frame_header, 6) == 0) {
                 avg_lum = ((data[35] >> 2) & 3) |
                            (data[20] << 2) |
                            (data[19] << 10);
@@ -2485,7 +2485,10 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
                 avg_lum >>= 9;
                 atomic_set(&sd->avg_lum, avg_lum);
                 gspca_frame_add(gspca_dev, LAST_PACKET, NULL, 0);
-                return;
+                len -= 64;
+                if (len == 0)
+                        return;
+                data += 64;
         }
         if (gspca_dev->last_packet_type == LAST_PACKET) {
                 if (gspca_dev->cam.cam_mode[(int) gspca_dev->curr_mode].priv