[media] gspca - sonixj: Update the JPEG quality for best image transfer

During image capture, the filling rate of the isoc packets is computed.
It is then used by a work queue to update the current JPEG quality.

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

diff --git a/drivers/media/video/gspca/sonixj.c b/drivers/media/video/gspca/sonixj.c
index d465022..2bfb8df 100644 (file)
--- a/drivers/media/video/gspca/sonixj.c
+++ b/drivers/media/video/gspca/sonixj.c
@@ -57,12 +57,18 @@ struct sd {
        atomic_t avg_lum;
        u32 exposure;
 
+       struct work_struct work;
+       struct workqueue_struct *work_thread;
+
+       u32 pktsz;                      /* (used by pkt_scan) */
+       u16 npkt;
+       u8 nchg;
        s8 short_mark;
 
        u8 quality;                     /* image quality */
-#define QUALITY_MIN 60
-#define QUALITY_MAX 95
-#define QUALITY_DEF 80
+#define QUALITY_MIN 25
+#define QUALITY_MAX 90
+#define QUALITY_DEF 70
 
        u8 reg01;
        u8 reg17;
@@ -100,6 +106,8 @@ enum sensors {
        SENSOR_SP80708,
 };
 
+static void qual_upd(struct work_struct *work);
+
 /* device flags */
 #define F_PDN_INV      0x01    /* inverse pin S_PWR_DN / sn_xxx tables */
 #define F_ILLUM                0x02    /* presence of illuminator */
@@ -1786,6 +1794,8 @@ static int sd_config(struct gspca_dev *gspca_dev,
        sd->ag_cnt = -1;
        sd->quality = QUALITY_DEF;
 
+       INIT_WORK(&sd->work, qual_upd);
+
        return 0;
 }
 
@@ -2297,6 +2307,19 @@ static void setjpegqual(struct gspca_dev *gspca_dev)
        reg_w1(gspca_dev, 0x18, sd->reg18);
 }
 
+/* JPEG quality update */
+/* This function is executed from a work queue. */
+static void qual_upd(struct work_struct *work)
+{
+       struct sd *sd = container_of(work, struct sd, work);
+       struct gspca_dev *gspca_dev = &sd->gspca_dev;
+
+       mutex_lock(&gspca_dev->usb_lock);
+       PDEBUG(D_STREAM, "qual_upd %d%%", sd->quality);
+       setjpegqual(gspca_dev);
+       mutex_unlock(&gspca_dev->usb_lock);
+}
+
 /* -- start the camera -- */
 static int sd_start(struct gspca_dev *gspca_dev)
 {
@@ -2610,6 +2633,11 @@ static int sd_start(struct gspca_dev *gspca_dev)
        setcolors(gspca_dev);
        setautogain(gspca_dev);
        setfreq(gspca_dev);
+
+       sd->pktsz = sd->npkt = 0;
+       sd->nchg = sd->short_mark = 0;
+       sd->work_thread = create_singlethread_workqueue(MODULE_NAME);
+
        return gspca_dev->usb_err;
 }
 
@@ -2686,6 +2714,20 @@ static void sd_stopN(struct gspca_dev *gspca_dev)
        /* reg_w1(gspca_dev, 0xf1, 0x01); */
 }
 
+/* called on streamoff with alt==0 and on disconnect */
+/* the usb_lock is held at entry - restore on exit */
+static void sd_stop0(struct gspca_dev *gspca_dev)
+{
+       struct sd *sd = (struct sd *) gspca_dev;
+
+       if (sd->work_thread != NULL) {
+               mutex_unlock(&gspca_dev->usb_lock);
+               destroy_workqueue(sd->work_thread);
+               mutex_lock(&gspca_dev->usb_lock);
+               sd->work_thread = NULL;
+       }
+}
+
 static void do_autogain(struct gspca_dev *gspca_dev)
 {
        struct sd *sd = (struct sd *) gspca_dev;
@@ -2778,7 +2820,7 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
                        int len)                        /* iso packet length */
 {
        struct sd *sd = (struct sd *) gspca_dev;
-       int i;
+       int i, new_qual;
 
        /*
         * A frame ends on the marker
@@ -2818,6 +2860,10 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
                data += i;
        }
 
+       /* count the packets and their size */
+       sd->npkt++;
+       sd->pktsz += len;
+
        /* search backwards if there is a marker in the packet */
        for (i = len - 1; --i >= 0; ) {
                if (data[i] != 0xff) {
@@ -2843,27 +2889,60 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
        return;
 
        /* marker found */
-       /* if some error, discard the frame */
+       /* if some error, discard the frame and decrease the quality */
 marker_found:
+       new_qual = 0;
        if (i > 2) {
                if (data[i - 2] != 0xff || data[i - 1] != 0xd9) {
                        gspca_dev->last_packet_type = DISCARD_PACKET;
+                       new_qual = -3;
                }
        } else if (i + 6 < len) {
                if (data[i + 6] & 0x08) {
                        gspca_dev->last_packet_type = DISCARD_PACKET;
+                       new_qual = -5;
                }
        }
 
        gspca_frame_add(gspca_dev, LAST_PACKET, data, i);
 
+       /* compute the filling rate and a new JPEG quality */
+       if (new_qual == 0) {
+               int r;
+
+               r = (sd->pktsz * 100) /
+                       (sd->npkt *
+                               gspca_dev->urb[0]->iso_frame_desc[0].length);
+               if (r >= 85)
+                       new_qual = -3;
+               else if (r < 75)
+                       new_qual = 2;
+       }
+       if (new_qual != 0) {
+               sd->nchg += new_qual;
+               if (sd->nchg < -6 || sd->nchg >= 12) {
+                       sd->nchg = 0;
+                       new_qual += sd->quality;
+                       if (new_qual < QUALITY_MIN)
+                               new_qual = QUALITY_MIN;
+                       else if (new_qual > QUALITY_MAX)
+                               new_qual = QUALITY_MAX;
+                       if (new_qual != sd->quality) {
+                               sd->quality = new_qual;
+                               queue_work(sd->work_thread, &sd->work);
+                       }
+               }
+       } else {
+               sd->nchg = 0;
+       }
+       sd->pktsz = sd->npkt = 0;
+
        /* if the marker is smaller than 62 bytes,
         * memorize the number of bytes to skip in the next packet */
        if (i + 62 > len) {                     /* no more usable data */
                sd->short_mark = i + 62 - len;
                return;
        }
-
        if (sd->ag_cnt >= 0)
                set_lum(sd, data + i);
 
@@ -2878,22 +2957,6 @@ marker_found:
        }
 }
 
-static int sd_set_jcomp(struct gspca_dev *gspca_dev,
-                       struct v4l2_jpegcompression *jcomp)
-{
-       struct sd *sd = (struct sd *) gspca_dev;
-
-       if (jcomp->quality < QUALITY_MIN)
-               sd->quality = QUALITY_MIN;
-       else if (jcomp->quality > QUALITY_MAX)
-               sd->quality = QUALITY_MAX;
-       else
-               sd->quality = jcomp->quality;
-       if (gspca_dev->streaming)
-               setjpegqual(gspca_dev);
-       return 0;
-}
-
 static int sd_get_jcomp(struct gspca_dev *gspca_dev,
                        struct v4l2_jpegcompression *jcomp)
 {
@@ -2955,10 +3018,10 @@ static const struct sd_desc sd_desc = {
        .init = sd_init,
        .start = sd_start,
        .stopN = sd_stopN,
+       .stop0 = sd_stop0,
        .pkt_scan = sd_pkt_scan,
        .dq_callback = do_autogain,
        .get_jcomp = sd_get_jcomp,
-       .set_jcomp = sd_set_jcomp,
        .querymenu = sd_querymenu,
 #if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
        .int_pkt_scan = sd_int_pkt_scan,