[PATCH v2 08/12] drm: bridge: samsung-dsim: Add atomic_check

[Jagan Teki]

On Wed, May 11, 2022 at 4:01 PM Andrzej Hajda <andrzej.hajda at intel.com> wrote:
>
> On 04.05.2022 13:40, Jagan Teki wrote:
> > Fixing up the mode flags is required in order to correlate the
> > correct sync flags of the surrounding components in the chain
> > to make sure the whole pipeline can work properly.
> >
> > So, handle the mode flags via bridge, atomic_check.
> >
> > v2:
> > * none
> >
> > v1:
> > * fix mode flags in atomic_check instead of mode_fixup
> >
> > Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> > ---
> >   drivers/gpu/drm/bridge/samsung-dsim.c | 14 ++++++++++++++
> >   1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> > index b618e52d0ee3..bd78cef890e4 100644
> > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > @@ -1340,6 +1340,19 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
> >       pm_runtime_put_sync(dsi->dev);
> >   }
> >
> > +static int samsung_dsim_atomic_check(struct drm_bridge *bridge,
> > +                                  struct drm_bridge_state *bridge_state,
> > +                                  struct drm_crtc_state *crtc_state,
> > +                                  struct drm_connector_state *conn_state)
> > +{
> > +     struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
> > +
> > +     adjusted_mode->flags |= (DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
> > +     adjusted_mode->flags &= ~(DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
>
>
> 1. Shouldn't this be in mode_fixup callback?

Possible to do it on mode_fixup, yes. if we want to do the same stuff
on atomic API then atomic_check is the proper helper.

> 2. Where this requirement comes from? As Marek says it breaks Samsung
> platforms and is against DSIM specification[1]:

At least the bridge chain starting from LCDIF+DSIM requires active high sync.

Jagan.