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authorHans de Goede <j.w.r.degoede@hhs.nl>2008-09-04 16:22:56 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2008-09-04 16:22:56 -0300
commitbf2a2202f75cda679303f09d150f9549f9835953 (patch)
tree5f5d6b2466e573b920fffa83c5d3eff1f59346d1 /drivers/media
parenta94a508691d16420ad10572a33db4d45115b5f75 (diff)
V4L/DVB (8870): gspca: Fix dark room problem with sonixb.
When using the sonixb driver in a dark room and given that the autoexposure algorithm starts with a setting most suitable for daylight, the picture produced by the cam may actually be 100% black leading to a avg_lum value of 0, so an avg_lum value of 0 does not always signal an exposure settings change (which it normally does). This patch adds a check for the really black image case and stops dropping all frames as invalid in this case. 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>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/video/gspca/sonixb.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/media/video/gspca/sonixb.c b/drivers/media/video/gspca/sonixb.c
index bde9ea9b980..64bc758fbae 100644
--- a/drivers/media/video/gspca/sonixb.c
+++ b/drivers/media/video/gspca/sonixb.c
@@ -52,6 +52,7 @@ MODULE_LICENSE("GPL");
struct sd {
struct gspca_dev gspca_dev; /* !! must be the first item */
atomic_t avg_lum;
+ int prev_avg_lum;
unsigned char gain;
unsigned char exposure;
@@ -1022,10 +1023,19 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
} else {
lum = data[i + 8] + (data[i + 9] << 8);
}
- if (lum == 0) {
+ /* When exposure changes midway a frame we
+ get a lum of 0 in this case drop 2 frames
+ as the frames directly after an exposure
+ change have an unstable image. Sometimes lum
+ *really* is 0 (cam used in low light with
+ low exposure setting), so do not drop frames
+ if the previous lum was 0 too. */
+ if (lum == 0 && sd->prev_avg_lum != 0) {
lum = -1;
sd->frames_to_drop = 2;
- }
+ sd->prev_avg_lum = 0;
+ } else
+ sd->prev_avg_lum = lum;
atomic_set(&sd->avg_lum, lum);
if (sd->frames_to_drop) {