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.
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.
>
> >
> > mbusformat = adv748x_csi2_get_pad_format(sd, sd_state, sdformat->pad,
> > sdformat->which);
> > --
> > 2.44.0
> >
>
> --
> Kind Regards,
> Niklas Söderlund
