V4L/DVB (8827): gspca: Stop pac7302 autogain oscillation.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 29 insertions, 19 deletions

diff --git a/drivers/media/video/gspca/pac7311.c b/drivers/media/video/gspca/pac7311.c
index 35244cf98511..723219d4964e 100644
--- a/drivers/media/video/gspca/pac7311.c
+++ b/drivers/media/video/gspca/pac7311.c
@@ -39,7 +39,7 @@
 
    Address      Description
    0x02         Clock divider 2-63, fps =~ 60 / val. Must be a multiple of 3 on
-                the 7302, so one of 3, 6, 9, ...
+                the 7302, so one of 3, 6, 9, ..., except when between 6 and 12?
    -/0x0f       Master gain 1-245, low value = high gain
    0x10/-       Master gain 0-31
    -/0x10       Another gain 0-15, limited influence (1-2x gain I guess)
@@ -626,8 +626,9 @@ static void setexposure(struct gspca_dev *gspca_dev)
 
         if (sd->sensor == SENSOR_PAC7302) {
                 /* On the pac7302 reg2 MUST be a multiple of 3, so round it to
-                   the nearest multiple of 3 */
-                reg = ((reg + 1) / 3) * 3;
+                   the nearest multiple of 3, except when between 6 and 12? */
+                if (reg < 6 || reg > 12)
+                        reg = ((reg + 1) / 3) * 3;
                 reg_w(gspca_dev, 0xff, 0x03);           /* page 3 */
                 reg_w(gspca_dev, 0x02, reg);
         } else {
@@ -761,20 +762,32 @@ static void do_autogain(struct gspca_dev *gspca_dev)
 {
         struct sd *sd = (struct sd *) gspca_dev;
         int avg_lum = atomic_read(&sd->avg_lum);
-        int desired_lum;
+        int desired_lum, deadzone;
 
         if (avg_lum == -1)
                 return;
 
-        if (sd->sensor == SENSOR_PAC7302)
-                desired_lum = 70 + sd->brightness * 2;
-        else
+        if (sd->sensor == SENSOR_PAC7302) {
+                desired_lum = 270 + sd->brightness * 4;
+                /* Hack hack, with the 7202 the first exposure step is
+                   pretty large, so if we're about to make the first
+                   exposure increase make the deadzone large to avoid
+                   oscilating */
+                if (desired_lum > avg_lum && sd->gain == GAIN_DEF &&
+                                sd->exposure > EXPOSURE_DEF &&
+                                sd->exposure < 42)
+                        deadzone = 90;
+                else
+                        deadzone = 30;
+        } else {
                 desired_lum = 200;
+                deadzone = 20;
+        }
 
         if (sd->autogain_ignore_frames > 0)
                 sd->autogain_ignore_frames--;
         else if (gspca_auto_gain_n_exposure(gspca_dev, avg_lum, desired_lum,
-                        10, GAIN_KNEE, EXPOSURE_KNEE))
+                        deadzone, GAIN_KNEE, EXPOSURE_KNEE))
                 sd->autogain_ignore_frames = PAC_AUTOGAIN_IGNORE_FRAMES;
 }
 
@@ -802,7 +815,11 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
                 int n, lum_offset, footer_length;
 
                 if (sd->sensor == SENSOR_PAC7302) {
-                  lum_offset = 34 + sizeof pac_sof_marker;
+                  /* 6 bytes after the FF D9 EOF marker a number of lumination
+                     bytes are send corresponding to different parts of the
+                     image, the 14th and 15th byte after the EOF seem to
+                     correspond to the center of the image */
+                  lum_offset = 61 + sizeof pac_sof_marker;
                   footer_length = 74;
                 } else {
                   lum_offset = 24 + sizeof pac_sof_marker;
@@ -829,18 +846,11 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
 
                 /* Get average lumination */
                 if (gspca_dev->last_packet_type == LAST_PACKET &&
-                                n >= lum_offset) {
-                        if (sd->sensor == SENSOR_PAC7302)
-                                atomic_set(&sd->avg_lum,
-                                                (data[-lum_offset] << 8) |
-                                                data[-lum_offset + 1]);
-                        else
-                                atomic_set(&sd->avg_lum,
-                                                data[-lum_offset] +
+                                n >= lum_offset)
+                        atomic_set(&sd->avg_lum, data[-lum_offset] +
                                                 data[-lum_offset + 1]);
-                } else {
+                else
                         atomic_set(&sd->avg_lum, -1);
-                }
 
                 /* Start the new frame with the jpeg header */
                 gspca_frame_add(gspca_dev, FIRST_PACKET, frame,