Re: [PATCH] drm/mediatek: only announce AFBC if really supported

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

On Tue, 2025-06-10 at 23:12 +0800, Icenowy Zheng wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
> 
> 
> 在 2025-05-31星期六的 20:11 +0800，Icenowy Zheng写道：
> > Currently even the SoC's OVL does not declare the support of AFBC,
> > AFBC
> > is still announced to the userspace within the IN_FORMATS blob, which
> > breaks modern Wayland compositors like KWin Wayland and others.
> > 
> > Gate passing modifiers to drm_universal_plane_init() behind querying
> > the
> > driver of the hardware block for AFBC support.
> > 
> > Fixes: c410fa9b07c3 ("drm/mediatek: Add AFBC support to Mediatek DRM
> > driver")
> > Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
> > ---
> 
> Ping.
> 
> This patch at least fixes running regular Wayland desktops on
> postmarketOS (I posted this patch there).

Reviewed-by: CK Hu <ck.hu@medaitek.com>

> 
> > Patch tested on MT8183, on which KWin Wayland 5.27.12 is fixed.
> > 
> > In addition, I tried to fake supports_afbc in mt8183_ovl_driver_data
> > and
> > mt8183_ovl_2l_driver_data, then KWin Wayland gets broken again and
> > modetest also shows the AFBC modifier in IN_FORMATS.
> > 
> >  drivers/gpu/drm/mediatek/mtk_crtc.c     | 3 ++-
> >  drivers/gpu/drm/mediatek/mtk_ddp_comp.c | 1 +
> >  drivers/gpu/drm/mediatek/mtk_ddp_comp.h | 9 +++++++++
> >  drivers/gpu/drm/mediatek/mtk_disp_drv.h | 1 +
> >  drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 7 +++++++
> >  drivers/gpu/drm/mediatek/mtk_plane.c    | 7 +++++--
> >  drivers/gpu/drm/mediatek/mtk_plane.h    | 3 ++-
> >  7 files changed, 27 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c
> > b/drivers/gpu/drm/mediatek/mtk_crtc.c
> > index 8f6fba4217ece..53359c2465b65 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_crtc.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
> > @@ -930,7 +930,8 @@ static int mtk_crtc_init_comp_planes(struct
> > drm_device *drm_dev,
> >                                 mtk_ddp_comp_supported_rotations(comp
> > ),
> >                                 mtk_ddp_comp_get_blend_modes(comp),
> >                                 mtk_ddp_comp_get_formats(comp),
> > -                               mtk_ddp_comp_get_num_formats(comp),
> > i);
> > +                               mtk_ddp_comp_get_num_formats(comp),
> > +                               mtk_ddp_comp_is_afbc_supported(comp),
> > i);
> >                 if (ret)
> >                         return ret;
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_ddp_comp.c
> > b/drivers/gpu/drm/mediatek/mtk_ddp_comp.c
> > index edc6417639e64..ac6620e10262e 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_ddp_comp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_ddp_comp.c
> > @@ -366,6 +366,7 @@ static const struct mtk_ddp_comp_funcs ddp_ovl =
> > {
> >         .get_blend_modes = mtk_ovl_get_blend_modes,
> >         .get_formats = mtk_ovl_get_formats,
> >         .get_num_formats = mtk_ovl_get_num_formats,
> > +       .is_afbc_supported = mtk_ovl_is_afbc_supported,
> >  };
> > 
> >  static const struct mtk_ddp_comp_funcs ddp_postmask = {
> > diff --git a/drivers/gpu/drm/mediatek/mtk_ddp_comp.h
> > b/drivers/gpu/drm/mediatek/mtk_ddp_comp.h
> > index 39720b27f4e9e..7289b3dcf22f2 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_ddp_comp.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_ddp_comp.h
> > @@ -83,6 +83,7 @@ struct mtk_ddp_comp_funcs {
> >         u32 (*get_blend_modes)(struct device *dev);
> >         const u32 *(*get_formats)(struct device *dev);
> >         size_t (*get_num_formats)(struct device *dev);
> > +       bool (*is_afbc_supported)(struct device *dev);
> >         void (*connect)(struct device *dev, struct device *mmsys_dev,
> > unsigned int next);
> >         void (*disconnect)(struct device *dev, struct device
> > *mmsys_dev, unsigned int next);
> >         void (*add)(struct device *dev, struct mtk_mutex *mutex);
> > @@ -294,6 +295,14 @@ size_t mtk_ddp_comp_get_num_formats(struct
> > mtk_ddp_comp *comp)
> >         return 0;
> >  }
> > 
> > +static inline bool mtk_ddp_comp_is_afbc_supported(struct
> > mtk_ddp_comp *comp)
> > +{
> > +       if (comp->funcs && comp->funcs->is_afbc_supported)
> > +               return comp->funcs->is_afbc_supported(comp->dev);
> > +
> > +       return false;
> > +}
> > +
> >  static inline bool mtk_ddp_comp_add(struct mtk_ddp_comp *comp,
> > struct mtk_mutex *mutex)
> >  {
> >         if (comp->funcs && comp->funcs->add) {
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > b/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > index 04217a36939cd..679d413bf10be 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > @@ -106,6 +106,7 @@ void mtk_ovl_disable_vblank(struct device *dev);
> >  u32 mtk_ovl_get_blend_modes(struct device *dev);
> >  const u32 *mtk_ovl_get_formats(struct device *dev);
> >  size_t mtk_ovl_get_num_formats(struct device *dev);
> > +bool mtk_ovl_is_afbc_supported(struct device *dev);
> > 
> >  void mtk_ovl_adaptor_add_comp(struct device *dev, struct mtk_mutex
> > *mutex);
> >  void mtk_ovl_adaptor_remove_comp(struct device *dev, struct
> > mtk_mutex *mutex);
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > index d0581c4e3c999..e0236353d4997 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > @@ -236,6 +236,13 @@ size_t mtk_ovl_get_num_formats(struct device
> > *dev)
> >         return ovl->data->num_formats;
> >  }
> > 
> > +bool mtk_ovl_is_afbc_supported(struct device *dev)
> > +{
> > +       struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
> > +
> > +       return ovl->data->supports_afbc;
> > +}
> > +
> >  int mtk_ovl_clk_enable(struct device *dev)
> >  {
> >         struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
> > diff --git a/drivers/gpu/drm/mediatek/mtk_plane.c
> > b/drivers/gpu/drm/mediatek/mtk_plane.c
> > index 655106bbb76d3..e08b771bc25e9 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_plane.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_plane.c
> > @@ -321,7 +321,8 @@ static const struct drm_plane_helper_funcs
> > mtk_plane_helper_funcs = {
> >  int mtk_plane_init(struct drm_device *dev, struct drm_plane *plane,
> >                    unsigned long possible_crtcs, enum drm_plane_type
> > type,
> >                    unsigned int supported_rotations, const u32
> > blend_modes,
> > -                  const u32 *formats, size_t num_formats, unsigned
> > int plane_idx)
> > +                  const u32 *formats, size_t num_formats,
> > +                  bool supports_afbc, unsigned int plane_idx)
> >  {
> >         int err;
> > 
> > @@ -332,7 +333,9 @@ int mtk_plane_init(struct drm_device *dev, struct
> > drm_plane *plane,
> > 
> >         err = drm_universal_plane_init(dev, plane, possible_crtcs,
> >                                        &mtk_plane_funcs, formats,
> > -                                      num_formats, modifiers, type,
> > NULL);
> > +                                      num_formats,
> > +                                      supports_afbc ? modifiers :
> > NULL,
> > +                                      type, NULL);
> >         if (err) {
> >                 DRM_ERROR("failed to initialize plane\n");
> >                 return err;
> > diff --git a/drivers/gpu/drm/mediatek/mtk_plane.h
> > b/drivers/gpu/drm/mediatek/mtk_plane.h
> > index 3b13b89989c7e..95c5fa5295d8a 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_plane.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_plane.h
> > @@ -49,5 +49,6 @@ to_mtk_plane_state(struct drm_plane_state *state)
> >  int mtk_plane_init(struct drm_device *dev, struct drm_plane *plane,
> >                    unsigned long possible_crtcs, enum drm_plane_type
> > type,
> >                    unsigned int supported_rotations, const u32
> > blend_modes,
> > -                  const u32 *formats, size_t num_formats, unsigned
> > int plane_idx);
> > +                  const u32 *formats, size_t num_formats,
> > +                  bool supports_afbc, unsigned int plane_idx);
> >  #endif
>