Hi Laurent, On Wed, Feb 21, 2018 at 10:28:06PM +0200, Laurent Pinchart wrote: > Hi Jacopo, > > On Tuesday, 20 February 2018 10:58:57 EET jacopo mondi wrote: > > On Mon, Feb 19, 2018 at 09:19:32PM +0200, Laurent Pinchart wrote: > > > On Monday, 19 February 2018 18:59:44 EET Jacopo Mondi wrote: > > >> The sensor driver sets mbus format colorspace information and sizes, > > >> but not ycbcr encoding, quantization and xfer function. When supplied > > >> with an badly initialized mbus frame format structure, those fields > > >> need to be set explicitly not to leave them uninitialized. This is > > >> tested by v4l2-compliance, which supplies a mbus format description > > >> structure and checks for all fields to be properly set. > > >> > > >> Without this commit, v4l2-compliance fails when testing formats with: > > >> fail: v4l2-test-formats.cpp(335): ycbcr_enc >= 0xff > > >> > > >> Signed-off-by: Jacopo Mondi <jacopo+rene...@jmondi.org> > > >> --- > > >> > > >> drivers/media/i2c/ov7670.c | 4 ++++ > > >> 1 file changed, 4 insertions(+) > > >> > > >> diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c > > >> index 25b26d4..61c472e 100644 > > >> --- a/drivers/media/i2c/ov7670.c > > >> +++ b/drivers/media/i2c/ov7670.c > > >> @@ -996,6 +996,10 @@ static int ov7670_try_fmt_internal(struct > > >> v4l2_subdev > > >> *sd, fmt->height = wsize->height; > > >> > > >> fmt->colorspace = ov7670_formats[index].colorspace; > > > > > > On a side note, if I'm not mistaken the colorspace field is set to SRGB > > > for all entries. Shouldn't you hardcode it here and remove the field ? > > > > > >> + fmt->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT; > > >> + fmt->quantization = V4L2_QUANTIZATION_DEFAULT; > > >> + fmt->xfer_func = V4L2_XFER_FUNC_DEFAULT; > > > > > > How about setting the values explicitly instead of relying on defaults ? > > > That would be V4L2_YCBCR_ENC_601, V4L2_QUANTIZATION_LIM_RANGE and > > > V4L2_XFER_FUNC_SRGB. And could you then check a captured frame to see if > > > the sensor outputs limited or full range ? > > > > This actually makes me wonder if those informations (ycbcb_enc, > > quantization and xfer_func) shouldn't actually be part of the > > supported format list... I blindly added those default fields in the > > try_fmt function, but I doubt they applies to all supported formats. > > > > Eg. the sensor supports YUYV as well as 2 RGB encodings (RGB444 and > > RGB 565) and 1 raw format (BGGR). I now have a question here: > > > > 1) ycbcr_enc transforms non-linear R'G'B' to Y'CbCr: does this > > applies to RGB and raw formats? I don't think so, and what value is > > the correct one for the ycbcr_enc field in this case? I assume > > xfer_func and quantization applies to all formats instead.. > > There's no encoding for RGB formats if I understand things correctly, so I'd > set ycbcr_enc to V4L2_YCBCR_ENC_DEFAULT. The transfer function and the > quantization apply to all formats, but I'd be surprised to find a sensor > outputting limited range for RGB.
Ack, we got the same understanding for RGB formats. I wonder if for those formats we wouldn't need a V4L2_YCBCR_ENC_NONE or similar... > > Have you been able to check whether the sensor outputs limited range of full > range YUV ? If it outputs full range you can hardcode quantization to > V4L2_QUANTIZATION_FULL_RANGE for all formats. In YUYV mode, I see values > 0xf0 ( > 240, which is the max value for CbCr samples in limited quantization range), so I assume quantization is full range. Actually the hardest part here was having a white enough surface to point the sensor to :) Thanks j > > > >> info->format = *fmt; > > >> > > >> return 0; > > -- > Regards, > > Laurent Pinchart >