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

[Jagan Teki]

On Mon, Jun 13, 2022 at 5:02 PM Marek Szyprowski
<m.szyprowski at samsung.com> wrote:
>
> On 13.06.2022 13:17, Jagan Teki wrote:
> > 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.
>
> Then please make this specific to the imx variant. The current version
> breaks DSI operation on all Exynos based boards.

But exynos trm also says the same?

"45.2.2.1.2 RGB Interface
Vsync, Hsync, and VDEN are active high signals"

Jagan.