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From:   Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Date:   Fri, 7 Jun 2019 11:37:55 -0300
Message-ID: <CADKXj+7OLRLrGo+YbxZjR7f90WNPPjT_rkcyt3GrxomCAjOjHA@mail.gmail.com>
Subject: Re: [PATCH 1/2] drm/vkms: Use index instead of 0 in possible crtc
To:     Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>,
        Brian Starkey <brian.starkey@arm.com>,
        Liviu Dudau <liviu.dudau@arm.com>,
        Haneen Mohammed <hamohammed.sa@gmail.com>,
        Simon Ser <contact@emersion.fr>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc:     Daniel Vetter <daniel@ffwll.ch>
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On Fri, Jun 7, 2019 at 4:40 AM Daniel Vetter <daniel@ffwll.ch> wrote:
>
> On Thu, Jun 06, 2019 at 07:40:38PM -0300, Rodrigo Siqueira wrote:
> > When vkms calls drm_universal_plane_init(), it sets 0 for the
> > possible_crtcs parameter which works well for a single encoder and
> > connector; however, this approach is not flexible and does not fit well
> > for vkms. This commit adds an index parameter for vkms_plane_init()
> > which makes code flexible and enables vkms to support other DRM features.
> >
> > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
>
> I think a core patch to WARN_ON if this is NULL would be good. Since
> that's indeed a bit broken ... We'd need to check all callers to make sure
> there's not other such bugs anywhere ofc.
> -Daniel

Do you mean add WARN_ON in `drm_universal_plane_init()` if
`possible_crtcs` is equal to zero?

> > ---
> >  drivers/gpu/drm/vkms/vkms_drv.c    | 2 +-
> >  drivers/gpu/drm/vkms/vkms_drv.h    | 4 ++--
> >  drivers/gpu/drm/vkms/vkms_output.c | 6 +++---
> >  drivers/gpu/drm/vkms/vkms_plane.c  | 4 ++--
> >  4 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> > index 738dd6206d85..92296bd8f623 100644
> > --- a/drivers/gpu/drm/vkms/vkms_drv.c
> > +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> > @@ -92,7 +92,7 @@ static int vkms_modeset_init(struct vkms_device *vkmsdev)
> >       dev->mode_config.max_height = YRES_MAX;
> >       dev->mode_config.preferred_depth = 24;
> >
> > -     return vkms_output_init(vkmsdev);
> > +     return vkms_output_init(vkmsdev, 0);
> >  }
> >
> >  static int __init vkms_init(void)
> > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> > index 81f1cfbeb936..e81073dea154 100644
> > --- a/drivers/gpu/drm/vkms/vkms_drv.h
> > +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> > @@ -113,10 +113,10 @@ bool vkms_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
> >                              int *max_error, ktime_t *vblank_time,
> >                              bool in_vblank_irq);
> >
> > -int vkms_output_init(struct vkms_device *vkmsdev);
> > +int vkms_output_init(struct vkms_device *vkmsdev, int index);
> >
> >  struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
> > -                               enum drm_plane_type type);
> > +                               enum drm_plane_type type, int index);
> >
> >  /* Gem stuff */
> >  struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
> > diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
> > index 3b162b25312e..1442b447c707 100644
> > --- a/drivers/gpu/drm/vkms/vkms_output.c
> > +++ b/drivers/gpu/drm/vkms/vkms_output.c
> > @@ -36,7 +36,7 @@ static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {
> >       .get_modes    = vkms_conn_get_modes,
> >  };
> >
> > -int vkms_output_init(struct vkms_device *vkmsdev)
> > +int vkms_output_init(struct vkms_device *vkmsdev, int index)
> >  {
> >       struct vkms_output *output = &vkmsdev->output;
> >       struct drm_device *dev = &vkmsdev->drm;
> > @@ -46,12 +46,12 @@ int vkms_output_init(struct vkms_device *vkmsdev)
> >       struct drm_plane *primary, *cursor = NULL;
> >       int ret;
> >
> > -     primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
> > +     primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY, index);
> >       if (IS_ERR(primary))
> >               return PTR_ERR(primary);
> >
> >       if (enable_cursor) {
> > -             cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
> > +             cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR, index);
> >               if (IS_ERR(cursor)) {
> >                       ret = PTR_ERR(cursor);
> >                       goto err_cursor;
> > diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> > index 0e67d2d42f0c..20ffc52f9194 100644
> > --- a/drivers/gpu/drm/vkms/vkms_plane.c
> > +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> > @@ -168,7 +168,7 @@ static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
> >  };
> >
> >  struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
> > -                               enum drm_plane_type type)
> > +                               enum drm_plane_type type, int index)
> >  {
> >       struct drm_device *dev = &vkmsdev->drm;
> >       const struct drm_plane_helper_funcs *funcs;
> > @@ -190,7 +190,7 @@ struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
> >               funcs = &vkms_primary_helper_funcs;
> >       }
> >
> > -     ret = drm_universal_plane_init(dev, plane, 0,
> > +     ret = drm_universal_plane_init(dev, plane, 1 << index,
> >                                      &vkms_plane_funcs,
> >                                      formats, nformats,
> >                                      NULL, type, NULL);
> > --
> > 2.21.0
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch


-- 

Rodrigo Siqueira
https://siqueira.tech