Re: [PATCH v3 0/7] drm/atomic: Add accessor macros for all atomic state.

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Maarten,

Thank you for the patches.

On Monday 16 Jan 2017 10:37:37 Maarten Lankhorst wrote:
> Fourth iteration. Instead of trying to convert all drivers straight away,
> implement all macros that are required to get state working.
> 
> Old situation:
> Use obj->state, which can refer to old or new state.
> Use drm_atomic_get_(existing_)obj_state, which can refer to new or old
> state. Use for_each_obj_in_state, which refers to new or old state.
> 
> New situation:
> 
> During atomic check:
> - Use drm_atomic_get_obj_state to add a object to the atomic state,
>   or get the new state.
> - Use drm_atomic_get_(old/new)_obj_state to peek at the new/old state,
>   without adding the object. This will return NULL if the object is
>   not part of the state. For planes and connectors the relevant crtc_state
>   is added, so this will work to get the crtc_state from obj_state->crtc
>   too, this means not having to write some error handling.
> 
> During atomic commit:
> - Do not use drm_atomic_get_obj_state, obj->state or
> drm_atomic_get_(existing_)obj_state any more, replace with
> drm_atomic_get_old/new_obj_state calls as required.

That will make driver code quite complicated :-/ I wonder if that's really a 
good solution. Maybe we should maintain obj->state only for the duration of 
the commit as a way to simplify drivers, and set it to NULL at all other times 
to avoid misusing it ? I know this contradicts the comment I've made in my 
review of patch 1/7, you can now choose which one to ignore :-)

> During both:
> - Use for_each_(new,old,oldnew)_obj_in_state to get the old or new state as
> needed. oldnew will be renamed to for_each_obj_in_state after all callers
> are converted to the new api.
> 
> When not doing atomic updates:
> Look at obj->state for now. I have some patches to fix this but I was asked
> to make it return a const state. This breaks a lot of users though so I
> skipped that patch in this iteration.
> 
> This series will return the correct state regardless of swapping.
> 
> Maarten Lankhorst (7):
>   drm/atomic: Add new iterators over all state, v3.
>   drm/atomic: Make add_affected_connectors look at crtc_state.
>   drm/atomic: Use new atomic iterator macros.
>   drm/atomic: Fix atomic helpers to use the new iterator macros.
>   drm/atomic: Add macros to access existing old/new state
>   drm/atomic: Convert get_existing_state callers to get_old/new_state, v2.
>   drm/blend: Use new atomic iterator macros.
> 
>  drivers/gpu/drm/drm_atomic.c         |  39 ++--
>  drivers/gpu/drm/drm_atomic_helper.c  | 377 ++++++++++++++++++--------------
>  drivers/gpu/drm/drm_blend.c          |  23 +--
>  drivers/gpu/drm/i915/intel_display.c |  13 +-
>  include/drm/drm_atomic.h             | 180 ++++++++++++++++-
>  include/drm/drm_atomic_helper.h      |   2 +
>  6 files changed, 438 insertions(+), 196 deletions(-)

-- 
Regards,

Laurent Pinchart

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