[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>

1 files changed, 86 insertions, 23 deletions

diff --git a/drivers/media/video/gspca/sonixj.c b/drivers/media/video/gspca/sonixj.c
index d465022b8022..2bfb8df9168b 100644
--- 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,