drm_connector_state without drm_atomic_state possible?

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hello,

I'm currently trying to get the TC9595 (tc358767.c) running on my imx93 
platform. For probing the EDID/DPCD information I need to put the DSI lanes 
into LP-11 (stop) state.
For this I was trying to call drm_atomic_bridge_chain_pre_enable() inside 
tc_connector_get_modes(), if bridge is not enabled not enabled yet. Please 
refer to [1] why pre_enable has to be called.

But at that point connector->state->state is NULL, while connector->state has 
some state. Thus drm_atomic_bridge_call_pre_enable(), called from 
drm_atomic_bridge_chain_pre_enable(), does nothing.

But this seems bogus to me, how can the backpointer to drm_atomic_state be 
NULL if the drm_connector_state from drm_connector is still valid?

Maybe I do not fully grasp the data organization and lifetime to it's fullest 
yet. Maybe someone has a suggestion how to pre_enable the bridge chain while 
get_modes is called.

Thanks and best regards,
Alexander

[1] https://lore.kernel.org/all/20221205173328.1395350-7-dave.stevenson@raspberrypi.com/
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