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

[Marek Szyprowski]

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.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland