Hello Jacopo,
On 2024-05-06 16:36:01 +0200, Jacopo Mondi wrote:
> Hi Niklas
>
> On Mon, May 06, 2024 at 04:12:01PM GMT, Niklas Söderlund wrote:
> > Hi Jacopo,
> >
> > On 2024-05-06 15:21:30 +0200, Jacopo Mondi wrote:
> > > Hi Niklas
> > >
> > > On Mon, May 06, 2024 at 01:37:30PM GMT, Niklas Söderlund wrote:
> > > > Hi Jacopo,
> > > >
> > > > Thanks for your work.
> > > >
> > > > On 2024-05-03 17:51:22 +0200, Jacopo Mondi wrote:
> > > > > The adv748x-csi2 driver configures the CSI-2 transmitter to
> > > > > automatically infer the image stream format from the connected
> > > > > frontend (HDMI or AFE).
> > > > >
> > > > > Setting a new format on the subdevice hence does not actually control
> > > > > the CSI-2 output format, but it's only there for the purpose of
> > > > > pipeline validation.
> > > > >
> > > > > However, there is currently no validation that the supplied media bus
> > > > > code is valid and supported by the device.
> > > > >
> > > > > With the introduction of enum_mbus_codes a list of supported format is
> > > > > now available, use it to validate that the supplied format is correct
> > > > > and use the default YUYV8 one if that's not the case.
> > > >
> > > > With the update tests for the change in patch 4 I hit multiple issues
> > > > with this patch for CVBS capture.
> > > >
> > > > >
> > > > > Signed-off-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
> > > > > ---
> > > > > drivers/media/i2c/adv748x/adv748x-csi2.c | 27 +++++++++++++++++++++++-
> > > > > 1 file changed, 26 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/media/i2c/adv748x/adv748x-csi2.c b/drivers/media/i2c/adv748x/adv748x-csi2.c
> > > > > index 219417b319a6..1aae6467ca62 100644
> > > > > --- a/drivers/media/i2c/adv748x/adv748x-csi2.c
> > > > > +++ b/drivers/media/i2c/adv748x/adv748x-csi2.c
> > > > > @@ -215,6 +215,23 @@ static int adv748x_csi2_get_format(struct v4l2_subdev *sd,
> > > > > return 0;
> > > > > }
> > > > >
> > > > > +static int adv748x_csi2_is_fmt_supported(struct adv748x_csi2 *tx,
> > > > > + unsigned int code)
> > > > > +{
> > > > > + const unsigned int *codes = is_txa(tx) ?
> > > > > + adv748x_csi2_txa_fmts :
> > > > > + adv748x_csi2_txb_fmts;
> > > > > + size_t num_fmts = is_txa(tx) ? ARRAY_SIZE(adv748x_csi2_txa_fmts)
> > > > > + : ARRAY_SIZE(adv748x_csi2_txb_fmts);
> > > > > +
> > > > > + for (unsigned int i = 0; i < num_fmts; i++) {
> > > > > + if (codes[i] == code)
> > > > > + return 0;
> > > > > + }
> > > > > +
> > > > > + return -EINVAL;
> > > > > +}
> > > > > +
> > > > > static int adv748x_csi2_set_format(struct v4l2_subdev *sd,
> > > > > struct v4l2_subdev_state *sd_state,
> > > > > struct v4l2_subdev_format *sdformat)
> > > > > @@ -222,7 +239,15 @@ static int adv748x_csi2_set_format(struct v4l2_subdev *sd,
> > > > > struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
> > > > > struct adv748x_state *state = tx->state;
> > > > > struct v4l2_mbus_framefmt *mbusformat;
> > > > > - int ret = 0;
> > > > > + int ret;
> > > > > +
> > > > > + /*
> > > > > + * Make sure the format is supported, if not default it to
> > > > > + * YUYV8 as it's supported by both TXes.
> > > > > + */
> > > > > + ret = adv748x_csi2_is_fmt_supported(tx, sdformat->format.code);
> > > > > + if (ret)
> > > > > + sdformat->format.code = MEDIA_BUS_FMT_YUYV8_1X16;
> > > >
> > > > If adv748x_csi2_is_fmt_supported() returns non-zero you default to
> > > > MEDIA_BUS_FMT_YUYV8_1X16, which is fine. But the non-zero return code is
> > > > propagated at the end of this function and to user-space falling the
> > > > IOCTL.
> > >
> > > Ouch, I think in my tests the error message got ignored
> > >
> > > >
> > > > Fixing that I hit another issue that kind of shows we need this format
> > > > validation ;-)
> > > >
> > > > The TXB entity only supports MEDIA_BUS_FMT_YUYV8_1X16 formats, the AFE
> > > > entity only outputs MEDIA_BUS_FMT_UYVY8_2X8... So with format validation
> > > > in place it becomes impossible to connect AFE to TXB and breaking CBVS
> > > > capture on Gen3. As a hack I added MEDIA_BUS_FMT_UYVY8_2X8 support to
> > > > TXB and I can again capture CVBS with patch 1-8 applied.
> > >
> > > Thanks for testing analog capture, I don't have a setup to easily do
> > > so.
> >
> > You can test it with the pattern generator on any Gen3 board.
> >
>
> ah well
>
> > >
> > > Should we make the AFE front-end produce 1X16 instead ? The format is
> > > only used between the AFE and TXs after all, changing it shouldn't
> > > have any implication on the interoperability with other devices.
> >
> > Not sure, the list of formats supported by each entity in the ADV748x is
> > added by patch 'media: adv748x-csi2: Implement enum_mbus_codes' in this
> > series.
>
> > Where did the list come from?
>
> From the chip datasheet ?
> Section 9.7 "MIPI Ouput format"
Thanks I found it now, maybe add that to the commit message of that
patch? I was hunting for register values in the register control manual
and found nothing ;-)
>
> >What formats do the AFE support?
>
> The AFE doesn't really "support" any format in my understanding. It
> connects to one of the two TXes with an internal processing pipeline,
> and the TX transmits the received video stream on the serial bus.
Ahh! I think we found the root of the issue we talked about the other
day in the VIN format handling about 1X16 vs 2x8 and CSI-2 ;-) That
likely came from this setting.
Yes, with the information from the datahseet I do think we should change
adv748x_afe_enum_mbus_code() to report MEDIA_BUS_FMT_YUYV8_1X16 instead
of MEDIA_BUS_FMT_UYVY8_2X8.
>
> > Why is the formats supported different between TXA and TXB ?
>
> You should ask the chip producer :)
If only we could. Imagine how much time we save if we could talk to them
and have datasheets instead of guessing half the time ;-)
>
> >
> > > >
> > > > >
> > > > > mbusformat = adv748x_csi2_get_pad_format(sd, sd_state, sdformat->pad,
> > > > > sdformat->which);
> > > > > --
> > > > > 2.44.0
> > > > >
> > > >
> > > > --
> > > > Kind Regards,
> > > > Niklas Söderlund
> >
> > --
> > Kind Regards,
> > Niklas Söderlund
> >
--
Kind Regards,
Niklas Söderlund
