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 <YiCF0Ze+mPxYQ2NP@paasikivi.fi.intel.com>
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From:   Kate Hsuan <hpa@redhat.com>
Date:   Wed, 9 Mar 2022 13:31:25 +0800
Message-ID: <CAEth8oFk8qq2yogwKGN62qfF_53Z7PKX8JxTa6qjz53ZbXCLdw@mail.gmail.com>
Subject: Re: [PATCH 1/1] staging: media: ipu3: Fix AF x_start position when
 rightmost stripe is used
To:     Sakari Ailus <sakari.ailus@linux.intel.com>
Cc:     Bingbu Cao <bingbu.cao@intel.com>,
        Tianshu Qiu <tian.shu.qiu@intel.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-media@vger.kernel.org, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org, Hans De Goede <hdegoede@redhat.com>,
        Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
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Precedence: bulk

Hi Sakari,

On Thu, Mar 3, 2022 at 5:09 PM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Kate,
>
> Thank you for the patch.
>
> On Wed, Feb 23, 2022 at 05:06:48PM +0800, Kate Hsuan wrote:
> > For the AF configuration, if the rightmost stripe is used, the AF scene
> > will be at the incorrect location of the sensor.
> >
> > The AF coordinate may be set to the right part of the sensor. This
> > configuration would lead to x_start being greater than the
> > down_scaled_stripes offset and the leftmost stripe would be disabled
> > and only the rightmost stripe is used to control the AF coordinate. If
> > the x_start doesn't perform any adjustments, the AF coordinate will be
> > at the wrong place of the sensor since down_scaled_stripes offset
> > would be the new zero of the coordinate system.
> >
> > In this patch, if only the rightmost stripe is used, x_start should
> > minus down_scaled_stripes offset to maintain its correctness of AF
> > scene coordinate.
> >
> > Signed-off-by: Kate Hsuan <hpa@redhat.com>
> > ---
> >  drivers/staging/media/ipu3/ipu3-css-params.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/media/ipu3/ipu3-css-params.c b/drivers/staging/media/ipu3/ipu3-css-params.c
> > index d9e3c3785075..efe4de8ef205 100644
> > --- a/drivers/staging/media/ipu3/ipu3-css-params.c
> > +++ b/drivers/staging/media/ipu3/ipu3-css-params.c
> > @@ -2556,6 +2556,14 @@ int imgu_css_cfg_acc(struct imgu_css *css, unsigned int pipe,
> >               /* Enable only for rightmost stripe, disable left */
> >               acc->af.stripes[0].grid_cfg.y_start &=
> >                       ~IPU3_UAPI_GRID_Y_START_EN;
> > +             acc->af.stripes[0].grid_cfg.x_start -=
> > +                     acc->stripe.down_scaled_stripes[1].offset;
> > +             acc->af.stripes[0].grid_cfg.x_end -=
> > +                     acc->stripe.down_scaled_stripes[1].offset;
> > +             acc->af.stripes[1].grid_cfg.x_start -=
> > +                     acc->stripe.down_scaled_stripes[1].offset;
> > +             acc->af.stripes[1].grid_cfg.x_end -=
> > +                     acc->stripe.down_scaled_stripes[1].offset;
>
> The grid x/y ends are calculated from the width when both grids are enabled
> and I think it should work the same way here. There's also masking of the
> bits that aren't in use.

Thanks for clarifying this :)

>
> The first stripe isn't enabled so changing values there has no effect as
> far as I can tell.
>

Okay. I would remove the setting of the first stripe in the v2 patch.

Thank you

> Looking at the code a little, it seems all awb_fr, ae and af seem to suffer
> from the same issue. Let's still iron out the fix for af first before
> considering those.
>
> >       } else if (acc->af.config.grid_cfg.x_end <=
> >                  acc->stripe.bds_out_stripes[0].width - min_overlap) {
> >               /* Enable only for leftmost stripe, disable right */
> > @@ -2563,7 +2571,6 @@ int imgu_css_cfg_acc(struct imgu_css *css, unsigned int pipe,
> >                       ~IPU3_UAPI_GRID_Y_START_EN;
> >       } else {
> >               /* Enable for both stripes */
> > -
> >               acc->af.stripes[0].grid_cfg.width =
> >                       (acc->stripe.bds_out_stripes[0].width - min_overlap -
> >                        acc->af.config.grid_cfg.x_start + 1) >>
>
> --
> Kind regards,
>
> Sakari Ailus
>


-- 
BR,
Kate