gspca_pac207: enable higher framerates / lower exposure settings

From: Hans de Goede <hdegoede@redhat.com>

Now that we've figured out the higher compression settings (supported in
libv4l-0.6.0 and later, so after this patch the driver should be used with
libv4l-0.6.0 or higher only!), we can enable higher framerates. Which
means lower exposure times, which is important for the use of the pac207
in full daylight.

This patch also tweakes the brightness default and the per color gain
balances to use the values which are adviced by Pixart in the pac207
application note.

Priority: normal

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 10 insertions, 18 deletions

diff --git a/linux/drivers/media/video/gspca/pac207.c b/linux/drivers/media/video/gspca/pac207.c
index f20d21b1c..96659433d 100644
--- a/linux/drivers/media/video/gspca/pac207.c
+++ b/linux/drivers/media/video/gspca/pac207.c
@@ -35,25 +35,17 @@ MODULE_LICENSE("GPL");
 
 #define PAC207_BRIGHTNESS_MIN		0
 #define PAC207_BRIGHTNESS_MAX		255
-#define PAC207_BRIGHTNESS_DEFAULT	4 /* power on default: 4 */
-
-/* An exposure value of 4 also works (3 does not) but then we need to lower
-   the compression balance setting when in 352x288 mode, otherwise the usb
-   bandwidth is not enough and packets get dropped resulting in corrupt
-   frames. The problem with this is that when the compression balance gets
-   lowered below 0x80, the pac207 starts using a different compression
-   algorithm for some lines, these lines get prefixed with a 0x2dd2 prefix
-   and currently we do not know how to decompress these lines, so for now
-   we use a minimum exposure value of 5 */
-#define PAC207_EXPOSURE_MIN		5
+#define PAC207_BRIGHTNESS_DEFAULT	46
+
+#define PAC207_EXPOSURE_MIN		3
 #define PAC207_EXPOSURE_MAX		26
-#define PAC207_EXPOSURE_DEFAULT		5 /* power on default: 3 ?? */
-#define PAC207_EXPOSURE_KNEE		11 /* 4 = 30 fps, 11 = 8, 15 = 6 */
+#define PAC207_EXPOSURE_DEFAULT		5 /* power on default: 3 */
+#define PAC207_EXPOSURE_KNEE		8 /* 4 = 30 fps, 11 = 8, 15 = 6 */
 
 #define PAC207_GAIN_MIN			0
 #define PAC207_GAIN_MAX			31
 #define PAC207_GAIN_DEFAULT         	9 /* power on default: 9 */
-#define PAC207_GAIN_KNEE		20
+#define PAC207_GAIN_KNEE		31
 
 #define PAC207_AUTOGAIN_DEADZONE	30
 
@@ -166,8 +158,8 @@ static const struct v4l2_pix_format sif_mode[] = {
 };
 
 static const __u8 pac207_sensor_init[][8] = {
-	{0x10, 0x12, 0x0d, 0x12, 0x0c, 0x01, 0x29, 0xf0},
-	{0x00, 0x64, 0x64, 0x64, 0x04, 0x10, 0xf0, 0x30},
+	{0x10, 0x12, 0x0d, 0x12, 0x0c, 0x01, 0x29, 0x84},
+	{0x49, 0x64, 0x64, 0x64, 0x04, 0x10, 0xf0, 0x30},
 	{0x00, 0x00, 0x00, 0x70, 0xa0, 0xf8, 0x00, 0x00},
 	{0x32, 0x00, 0x96, 0x00, 0xA2, 0x02, 0xaf, 0x00},
 };
@@ -290,7 +282,7 @@ static int sd_start(struct gspca_dev *gspca_dev)
 	if (gspca_dev->width == 176)
 		pac207_write_reg(gspca_dev, 0x4a, 0xff);
 	else
-		pac207_write_reg(gspca_dev, 0x4a, 0x88);
+		pac207_write_reg(gspca_dev, 0x4a, 0x30);
 	pac207_write_reg(gspca_dev, 0x4b, 0x00); /* Sram test value */
 	pac207_write_reg(gspca_dev, 0x08, sd->brightness);
 
@@ -339,7 +331,7 @@ static void pac207_do_auto_gain(struct gspca_dev *gspca_dev)
 	if (sd->autogain_ignore_frames > 0)
 		sd->autogain_ignore_frames--;
 	else if (gspca_auto_gain_n_exposure(gspca_dev, avg_lum,
-			100 + sd->brightness / 2, PAC207_AUTOGAIN_DEADZONE,
+			100, PAC207_AUTOGAIN_DEADZONE,
 			PAC207_GAIN_KNEE, PAC207_EXPOSURE_KNEE))
 		sd->autogain_ignore_frames = PAC_AUTOGAIN_IGNORE_FRAMES;
 }