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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Thu, 27 Aug 2020 07:01:56 +0800
Message-ID: <CAAOTY__OfwCN4_GyyvyYRHfFh_7iRYVKtiR1ieV_Q9ijhEJw+g@mail.gmail.com>
Subject: Re: [PATCH v2] drm/mediatek: dsi: fix scrolling of panel with small
 hfp or hbp
To:     Chun-Kuang Hu <chunkuang.hu@kernel.org>
Cc:     Jitao Shi <jitao.shi@mediatek.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        devicetree@vger.kernel.org,
        srv_heupstream <srv_heupstream@mediatek.com>,
        huijuan.xie@mediatek.com, stonea168@163.com,
        cawa.cheng@mediatek.com,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Bibby Hsieh <bibby.hsieh@mediatek.com>,
        CK Hu <ck.hu@mediatek.com>, yingjoe.chen@mediatek.com,
        eddie.huang@mediatek.com,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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Hi, Jitao:

Chun-Kuang Hu <chunkuang.hu@kernel.org> =E6=96=BC 2020=E5=B9=B48=E6=9C=8818=
=E6=97=A5 =E9=80=B1=E4=BA=8C =E4=B8=8B=E5=8D=8810:45=E5=AF=AB=E9=81=93=EF=
=BC=9A
>
> Hi, Jitao:
>
> Jitao Shi <jitao.shi@mediatek.com> =E6=96=BC 2020=E5=B9=B48=E6=9C=8818=E6=
=97=A5 =E9=80=B1=E4=BA=8C =E4=B8=8A=E5=8D=8810:41=E5=AF=AB=E9=81=93=EF=BC=
=9A
> >
> > On Tue, 2020-08-18 at 07:42 +0800, Chun-Kuang Hu wrote:
> > > Hi, Jitao:
> > >
> > > Jitao Shi <jitao.shi@mediatek.com> =E6=96=BC 2020=E5=B9=B48=E6=9C=881=
7=E6=97=A5 =E9=80=B1=E4=B8=80 =E4=B8=8B=E5=8D=889:07=E5=AF=AB=E9=81=93=EF=
=BC=9A
> > > >
> > > > horizontal_backporch_byte should be hbp * bpp - hbp extra bytes.
> > > > So remove the wrong subtraction 10.
> > > >
> > > > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> > > > ---
> > > >  drivers/gpu/drm/mediatek/mtk_dsi.c | 9 ++++-----
> > > >  1 file changed, 4 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/m=
ediatek/mtk_dsi.c
> > > > index 270bf22c98fe..5d031e634571 100644
> > > > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > > > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > > > @@ -473,14 +473,13 @@ static void mtk_dsi_config_vdo_timing(struct =
mtk_dsi *dsi)
> > > >         horizontal_sync_active_byte =3D (vm->hsync_len * dsi_tmp_bu=
f_bpp - 10);
> > >
> > > So this subtraction 10 is correct?
> > >
> > > Regards,
> > > Chun-Kuang.
> > >
> >
> > Yes, It is right.
> >
> > In the cea861 and dmt spec the mini hsync is 40 pixels.
> > So the vm->hsync_len * dsi_tmp_buf_bpp >=3D 120 > 10
> >
>
> OK, so
>
> Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
>

Applied to mediatek-drm-fixes [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/=
log/?h=3Dmediatek-drm-fixes

Regards,
Chun-Kuang.

> > Best Regards
> > jitao
> > > >
> > > >         if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> > > > -               horizontal_backporch_byte =3D
> > > > -                       (vm->hback_porch * dsi_tmp_buf_bpp - 10);
> > > > +               horizontal_backporch_byte =3D vm->hback_porch * dsi=
_tmp_buf_bpp;
> > > >         else
> > > > -               horizontal_backporch_byte =3D ((vm->hback_porch + v=
m->hsync_len) *
> > > > -                       dsi_tmp_buf_bpp - 10);
> > > > +               horizontal_backporch_byte =3D (vm->hback_porch + vm=
->hsync_len) *
> > > > +                                           dsi_tmp_buf_bpp;
> > > >
> > > >         data_phy_cycles =3D timing->lpx + timing->da_hs_prepare +
> > > > -                         timing->da_hs_zero + timing->da_hs_exit +=
 3;
> > > > +                         timing->da_hs_zero + timing->da_hs_exit;
> > > >
> > > >         if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
> > > >                 if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_=
buf_bpp >
> > > > --
> > > > 2.12.5
> > > > _______________________________________________
> > > > Linux-mediatek mailing list
> > > > Linux-mediatek@lists.infradead.org
> > > > http://lists.infradead.org/mailman/listinfo/linux-mediatek
> >