Hi, Guennadi! I have found interesting issue with mt9p031 camera driver. As far as I got the value of hblank in the kernel driver is not calculated correctly. According to the datasheet, the minimum horizontal blanking value should be calculated using the following formula: 346 x (Row_Bin + 1) + 64 + (Wdc / 2) If I'm right, it should look like in the code attached. Also I wonder why it is decided to use the default value for vblank, when it's said that is also should be calculated like this: vblank = max(8, SW - H) + 1, where SW - shutter width, H - output image height. Also, there might be an issue with the calculation of xskip/yskip within the same function (mt9p031_set_params). xskip = DIV_ROUND_CLOSEST(crop->width, format->width); yskip = DIV_ROUND_CLOSEST(crop->height, format->height); As far as I got, these values are calculated using the predefined macros, that rounds the calculated value to the nearest integer number. I faced with the problem, that these values rounded correctly when the result is > 1 (e.g. 1,5 will be rounded to 1). But what concerns the value 0,8 it will be rounded to 0 by this function (DIV_ROUND_CLOSEST). Could you please confirm this issue? With best regards, Andrei Andreyanau Signed-off-by: Andrei Andreyanau <a.andreyanau@xxxxxxxxxxxxxxxxx> diff --git a/drivers/media/i2c/mt9p031.c b/drivers/media/i2c/mt9p031.c index e328332..838b300 100644 --- a/drivers/media/i2c/mt9p031.c +++ b/drivers/media/i2c/mt9p031.c @@ -368,7 +368,7 @@ static int mt9p031_set_params(struct mt9p031 *mt9p031) /* Blanking - use minimum value for horizontal blanking and default * value for vertical blanking. */ - hblank = 346 * ybin + 64 + (80 >> min_t(unsigned int, xbin, 3)); + hblank = 346 * (xbin + 1) + 64 + ((80 >> clamp_t(unsigned int, xbin, 0, 3)) / 2); vblank = MT9P031_VERTICAL_BLANK_DEF; ret = mt9p031_write(client, MT9P031_HORIZONTAL_BLANK, hblank - 1); -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
