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V4L/DVB (11105): gspca - ov534: Adjust the packet scan function

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- change max payload size to 2040 bytes (was 2048)
- optimize

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Jean-Francois Moine 2009-03-19 06:12:59 -03:00 committed by Mauro Carvalho Chehab
parent 3481c19854
commit 84fbdf87ab
1 changed files with 60 additions and 61 deletions
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121
drivers/media/video/gspca/ov534.c
View file

@ -46,9 +46,9 @@ MODULE_LICENSE("GPL");
/* specific webcam descriptor */
struct sd {
struct gspca_dev gspca_dev; /* !! must be the first item */
__u32 last_fid;
__u32 last_pts;
int frame_rate;
u16 last_fid;
u8 frame_rate;
};
/* V4L2 controls supported by the driver */
@ -428,76 +428,75 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev, struct gspca_frame *frame,
{
struct sd *sd = (struct sd *) gspca_dev;
__u32 this_pts;
int this_fid;
u16 this_fid;
int remaining_len = len;
__u8 *next_data = data;
scan_next:
if (remaining_len <= 0)
return;
do {
len = min(remaining_len, 2040); /*fixme: was 2048*/
data = next_data;
len = min(remaining_len, 2048);
remaining_len -= len;
next_data += len;
/* Payloads are prefixed with a UVC-style header. We
consider a frame to start when the FID toggles, or the PTS
changes. A frame ends when EOF is set, and we've received
the correct number of bytes. */
/* Payloads are prefixed with a UVC-style header. We
consider a frame to start when the FID toggles, or the PTS
changes. A frame ends when EOF is set, and we've received
the correct number of bytes. */
/* Verify UVC header. Header length is always 12 */
if (data[0] != 12 || len < 12) {
PDEBUG(D_PACK, "bad header");
goto discard;
}
/* Check errors */
if (data[1] & UVC_STREAM_ERR) {
PDEBUG(D_PACK, "payload error");
goto discard;
}
/* Extract PTS and FID */
if (!(data[1] & UVC_STREAM_PTS)) {
PDEBUG(D_PACK, "PTS not present");
goto discard;
}
this_pts = (data[5] << 24) | (data[4] << 16) | (data[3] << 8) | data[2];
this_fid = (data[1] & UVC_STREAM_FID) ? 1 : 0;
/* If PTS or FID has changed, start a new frame. */
if (this_pts != sd->last_pts || this_fid != sd->last_fid) {
gspca_frame_add(gspca_dev, FIRST_PACKET, frame, NULL, 0);
sd->last_pts = this_pts;
sd->last_fid = this_fid;
}
/* Add the data from this payload */
gspca_frame_add(gspca_dev, INTER_PACKET, frame,
data + 12, len - 12);
/* If this packet is marked as EOF, end the frame */
if (data[1] & UVC_STREAM_EOF) {
sd->last_pts = 0;
if ((frame->data_end - frame->data) !=
(gspca_dev->width * gspca_dev->height * 2)) {
PDEBUG(D_PACK, "short frame");
/* Verify UVC header. Header length is always 12 */
if (data[0] != 12 || len < 12) {
PDEBUG(D_PACK, "bad header");
goto discard;
}
frame = gspca_frame_add(gspca_dev, LAST_PACKET, frame,
NULL, 0);
/* Check errors */
if (data[1] & UVC_STREAM_ERR) {
PDEBUG(D_PACK, "payload error");
goto discard;
}
/* Done this payload */
goto scan_next;
/* Extract PTS and FID */
if (!(data[1] & UVC_STREAM_PTS)) {
PDEBUG(D_PACK, "PTS not present");
goto discard;
}
this_pts = (data[5] << 24) | (data[4] << 16)
| (data[3] << 8) | data[2];
this_fid = (data[1] & UVC_STREAM_FID) ? 1 : 0;
/* If PTS or FID has changed, start a new frame. */
if (this_pts != sd->last_pts || this_fid != sd->last_fid) {
gspca_frame_add(gspca_dev, FIRST_PACKET, frame,
NULL, 0);
sd->last_pts = this_pts;
sd->last_fid = this_fid;
}
/* Add the data from this payload */
gspca_frame_add(gspca_dev, INTER_PACKET, frame,
data + 12, len - 12);
/* If this packet is marked as EOF, end the frame */
if (data[1] & UVC_STREAM_EOF) {
sd->last_pts = 0;
if (frame->data_end - frame->data !=
gspca_dev->width * gspca_dev->height * 2) {
PDEBUG(D_PACK, "short frame");
goto discard;
}
frame = gspca_frame_add(gspca_dev, LAST_PACKET, frame,
NULL, 0);
}
/* Done this payload */
goto scan_next;
discard:
/* Discard data until a new frame starts. */
gspca_frame_add(gspca_dev, DISCARD_PACKET, frame, NULL, 0);
goto scan_next;
/* Discard data until a new frame starts. */
gspca_frame_add(gspca_dev, DISCARD_PACKET, frame, NULL, 0);
scan_next:
remaining_len -= len;
data += len;
} while (remaining_len > 0);
}
/* get stream parameters (framerate) */