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References: <20230905084922.3908121-1-mwalle@kernel.org> <20230905084922.3908121-2-mwalle@kernel.org>
 <93576c3b04c8378c5c9296ec7a6585d9@kernel.org>
In-Reply-To: <93576c3b04c8378c5c9296ec7a6585d9@kernel.org>
From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Thu, 23 Nov 2023 23:33:17 +0800
Message-ID: <CAAOTY__LqKkj7Exg=wr0QUD-AQ_i3adXLUSdT2M_oYj7iCBAKQ@mail.gmail.com>
Subject: Re: [PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation
To:     Michael Walle <mwalle@kernel.org>
Cc:     =?UTF-8?B?TsOtY29sYXMgRiAuIFIgLiBBIC4gUHJhZG8=?= 
        <nfraprado@collabora.com>, Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        "Nancy . Lin" <nancy.lin@mediatek.com>,
        Frank Wunderlich <frank-w@public-files.de>,
        Jitao Shi <jitao.shi@mediatek.com>,
        Stu Hsieh <stu.hsieh@mediatek.com>,
        dri-devel@lists.freedesktop.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        "Jason-JH.Lin" <jason-jh.lin@mediatek.com>
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Hi, Michael:

Michael Walle <mwalle@kernel.org> =E6=96=BC 2023=E5=B9=B411=E6=9C=8821=E6=
=97=A5 =E9=80=B1=E4=BA=8C =E4=B8=8B=E5=8D=8810:44=E5=AF=AB=E9=81=93=EF=BC=
=9A
>
> Hi,
>
> > mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
> > always have the CRTC with id 0, the ext id 1 and the third id 2. This
> > is only true if the paths are all available. But paths are optional
> > (see
> > also comment in mtk_drm_kms_init()), e.g. the main path might not be
> > enabled or available at all. Then the CRTC IDs will shift one up, e.g.
> > ext will be 0 and the third path will be 1.
> >
> > To fix that, dynamically calculate the IDs by the presence of the
> > paths.
> >
> > While at it, make the return code a signed one and return -ENOENT if no
> > path is found and handle the error in the callers.
> >
> > Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting
> > possible_crtc way")
> > Suggested-by: N=C3=ADcolas F. R. A. Prado <nfraprado@collabora.com>
> > Signed-off-by: Michael Walle <mwalle@kernel.org>
> > Reviewed-by: N=C3=ADcolas F. R. A. Prado <nfraprado@collabora.com>
> > Tested-by: N=C3=ADcolas F. R. A. Prado <nfraprado@collabora.com>
>
> Is there anything wrong with these two patches? They are now lingering
> around for more than two months.
>
> Unfortunately, patch 2/2 won't apply anymore because of commit
> 01389b324c97 ("drm/mediatek: Add connector dynamic selection
> capability). And I'm a bit puzzled for what the crtc_id is used
> there because I guess it will have the same problem this patch
> fixes.

Please base on the latest kernel version to fix.

Regards,
Chun-Kuang.

>
> -michael
>
> > ---
> > v4:
> >  - return -ENOENT if mtk_drm_find_possible_crtc_by_comp() doesn't find
> >    any path
> > v3:
> >  - use data instead of priv_n->data
> >  - fixed typos
> >  - collected Rb and Tb tags
> > v2:
> >  - iterate over all_drm_private[] to get any vdosys
> >  - new check if a path is available
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dpi.c          |  5 +-
> >  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 75 ++++++++++++++++-----
> >  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |  3 +-
> >  drivers/gpu/drm/mediatek/mtk_dsi.c          |  5 +-
> >  4 files changed, 68 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index 2f931e4e2b60..f9250f7ee706 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -796,7 +796,10 @@ static int mtk_dpi_bind(struct device *dev, struct
> > device *master, void *data)
> >               return ret;
> >       }
> >
> > -     dpi->encoder.possible_crtcs =3D
> > mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> > +     ret =3D mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> > +     if (ret < 0)
> > +             goto err_cleanup;
> > +     dpi->encoder.possible_crtcs =3D ret;
> >
> >       ret =3D drm_bridge_attach(&dpi->encoder, &dpi->bridge, NULL,
> >                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > index 771f4e173353..83ae75ecd858 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > @@ -507,6 +507,27 @@ static bool mtk_drm_find_comp_in_ddp(struct device
> > *dev,
> >       return false;
> >  }
> >
> > +static bool mtk_ddp_path_available(const unsigned int *path,
> > +                                unsigned int path_len,
> > +                                struct device_node **comp_node)
> > +{
> > +     unsigned int i;
> > +
> > +     if (!path)
> > +             return false;
> > +
> > +     for (i =3D 0U; i < path_len; i++) {
> > +             /* OVL_ADAPTOR doesn't have a device node */
> > +             if (path[i] =3D=3D DDP_COMPONENT_DRM_OVL_ADAPTOR)
> > +                     continue;
> > +
> > +             if (!comp_node[path[i]])
> > +                     return false;
> > +     }
> > +
> > +     return true;
> > +}
> > +
> >  int mtk_ddp_comp_get_id(struct device_node *node,
> >                       enum mtk_ddp_comp_type comp_type)
> >  {
> > @@ -522,25 +543,47 @@ int mtk_ddp_comp_get_id(struct device_node *node,
> >       return -EINVAL;
> >  }
> >
> > -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device
> > *drm,
> > -                                             struct device *dev)
> > +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct
> > device *dev)
> >  {
> >       struct mtk_drm_private *private =3D drm->dev_private;
> > -     unsigned int ret =3D 0;
> > -
> > -     if (mtk_drm_find_comp_in_ddp(dev, private->data->main_path,
> > private->data->main_len,
> > -                                  private->ddp_comp))
> > -             ret =3D BIT(0);
> > -     else if (mtk_drm_find_comp_in_ddp(dev, private->data->ext_path,
> > -                                       private->data->ext_len, private=
->ddp_comp))
> > -             ret =3D BIT(1);
> > -     else if (mtk_drm_find_comp_in_ddp(dev, private->data->third_path,
> > -                                       private->data->third_len, priva=
te->ddp_comp))
> > -             ret =3D BIT(2);
> > -     else
> > -             DRM_INFO("Failed to find comp in ddp table\n");
> > +     const struct mtk_mmsys_driver_data *data;
> > +     struct mtk_drm_private *priv_n;
> > +     int i =3D 0, j;
> > +
> > +     for (j =3D 0; j < private->data->mmsys_dev_num; j++) {
> > +             priv_n =3D private->all_drm_private[j];
> > +             data =3D priv_n->data;
> > +
> > +             if (mtk_ddp_path_available(data->main_path, data->main_le=
n,
> > +                                        priv_n->comp_node)) {
> > +                     if (mtk_drm_find_comp_in_ddp(dev, data->main_path=
,
> > +                                                  data->main_len,
> > +                                                  priv_n->ddp_comp))
> > +                             return BIT(i);
> > +                     i++;
> > +             }
> > +
> > +             if (mtk_ddp_path_available(data->ext_path, data->ext_len,
> > +                                        priv_n->comp_node)) {
> > +                     if (mtk_drm_find_comp_in_ddp(dev, data->ext_path,
> > +                                                  data->ext_len,
> > +                                                  priv_n->ddp_comp))
> > +                             return BIT(i);
> > +                     i++;
> > +             }
> > +
> > +             if (mtk_ddp_path_available(data->third_path, data->third_=
len,
> > +                                        priv_n->comp_node)) {
> > +                     if (mtk_drm_find_comp_in_ddp(dev, data->third_pat=
h,
> > +                                                  data->third_len,
> > +                                                  priv_n->ddp_comp))
> > +                             return BIT(i);
> > +                     i++;
> > +             }
> > +     }
> >
> > -     return ret;
> > +     DRM_INFO("Failed to find comp in ddp table\n");
> > +     return -ENOENT;
> >  }
> >
> >  int mtk_ddp_comp_init(struct device_node *node, struct mtk_ddp_comp
> > *comp,
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > index febcaeef16a1..6a95df72de0a 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > @@ -277,8 +277,7 @@ static inline bool mtk_ddp_comp_disconnect(struct
> > mtk_ddp_comp *comp, struct dev
> >
> >  int mtk_ddp_comp_get_id(struct device_node *node,
> >                       enum mtk_ddp_comp_type comp_type);
> > -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device
> > *drm,
> > -                                             struct device *dev);
> > +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct
> > device *dev);
> >  int mtk_ddp_comp_init(struct device_node *comp_node, struct
> > mtk_ddp_comp *comp,
> >                     unsigned int comp_id);
> >  enum mtk_ddp_comp_type mtk_ddp_comp_get_type(unsigned int comp_id);
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index d8bfc2cce54d..d67e5c61a9b9 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -843,7 +843,10 @@ static int mtk_dsi_encoder_init(struct drm_device
> > *drm, struct mtk_dsi *dsi)
> >               return ret;
> >       }
> >
> > -     dsi->encoder.possible_crtcs =3D mtk_drm_find_possible_crtc_by_com=
p(drm,
> > dsi->host.dev);
> > +     ret =3D mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> > +     if (ret < 0)
> > +             goto err_cleanup_encoder;
> > +     dsi->encoder.possible_crtcs =3D ret;
> >
> >       ret =3D drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> >                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);