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aes2550: Harden against low finger pressure

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Stop scan only after 3rd heartbeat message

https://bugs.freedesktop.org/show_bug.cgi?id=56782
This commit is contained in:
Vasily Khoruzhick 2012-11-03 18:30:43 +03:00 • committed by Bastien Nocera
parent 9e92d4cf2c
commit 39902374ce
1 changed files with 14 additions and 4 deletions
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18
libfprint/drivers/aes2550.c
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@ -59,6 +59,7 @@ struct aes2550_dev {
GSList *strips; GSList *strips;
size_t strips_len; size_t strips_len;
gboolean deactivating; gboolean deactivating;
int heartbeat_cnt;
}; };
/****** IMAGE PROCESSING ******/ /****** IMAGE PROCESSING ******/
@ -369,6 +370,7 @@ static void capture_set_idle_reqs_cb(struct libusb_transfer *transfer)
static void capture_read_data_cb(struct libusb_transfer *transfer) static void capture_read_data_cb(struct libusb_transfer *transfer)
{ {
struct fpi_ssm *ssm = transfer->user_data; struct fpi_ssm *ssm = transfer->user_data;
struct aes2550_dev *aesdev = ssm->priv;
unsigned char *data = transfer->buffer; unsigned char *data = transfer->buffer;
int r; int r;
@ -390,14 +392,21 @@ static void capture_read_data_cb(struct libusb_transfer *transfer)
fpi_ssm_mark_aborted(ssm, -EPROTO); fpi_ssm_mark_aborted(ssm, -EPROTO);
goto out; goto out;
} }
aesdev->heartbeat_cnt = 0;
fpi_ssm_jump_to_state(ssm, CAPTURE_READ_DATA); fpi_ssm_jump_to_state(ssm, CAPTURE_READ_DATA);
break; break;
case AES2550_HEARTBEAT_SIZE: case AES2550_HEARTBEAT_SIZE:
if (data[0] == AES2550_HEARTBEAT_MAGIC) { if (data[0] == AES2550_HEARTBEAT_MAGIC) {
/* No data for a long time, looks like finger was removed (or no movement) */ /* No data for a long time => finger was removed or there's no movement */
/* assemble image and submit it to library */ aesdev->heartbeat_cnt++;
fp_dbg("Got heartbeat => last frame"); if (aesdev->heartbeat_cnt == 3) {
fpi_ssm_next_state(ssm); /* Got 3 heartbeat message, that's enough to consider that finger was removed,
* assemble image and submit it to the library */
fp_dbg("Got 3 heartbeats => finger removed");
fpi_ssm_next_state(ssm);
} else {
fpi_ssm_jump_to_state(ssm, CAPTURE_READ_DATA);
}
} }
break; break;
default: default:
@ -498,6 +507,7 @@ static void start_capture(struct fp_img_dev *dev)
return; return;
} }
aesdev->heartbeat_cnt = 0;
ssm = fpi_ssm_new(dev->dev, capture_run_state, CAPTURE_NUM_STATES); ssm = fpi_ssm_new(dev->dev, capture_run_state, CAPTURE_NUM_STATES);
fp_dbg(""); fp_dbg("");
ssm->priv = dev; ssm->priv = dev;