xref: /openbmc/linux/drivers/gpu/drm/amd/display/TODO (revision e1cb3e48)

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TODOs
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1. Base this on drm-next - WIP


2. Cleanup commit history


3. WIP - Drop page flip helper and use DRM's version


4. DONE - Flatten all DC objects
    * dc_stream/core_stream/stream should just be dc_stream
    * Same for other DC objects

    "Is there any major reason to keep all those abstractions?

    Could you collapse everything into struct dc_stream?

    I haven't looked recently but I didn't get the impression there was a
    lot of design around what was public/protected, more whatever needed
    to be used by someone else was in public."
    ~ Dave Airlie


5. DONE - Rename DC objects to align more with DRM
    * dc_surface -> dc_plane_state
    * dc_stream -> dc_stream_state


6. DONE - Per-plane and per-stream validation


7. WIP - Per-plane and per-stream commit


8. WIP - Split pipe_ctx into plane and stream resource structs


9. Attach plane and stream reources to state object instead of validate_context


10. Remove dc_edid_caps and drm_helpers_parse_edid_caps
    * Use drm_display_info instead
    * Remove DC's edid quirks and rely on DRM's quirks (add quirks if needed)

    "Making sure you use the sink-specific helper libraries and kernel
    subsystems, since there's really no good reason to have 2nd
    implementation of those in the kernel. Looks likes that's done for mst
    and edid parsing. There's still a bit a midlayer feeling to the edid
    parsing side (e.g. dc_edid_caps and dm_helpers_parse_edid_caps, I
    think it'd be much better if you convert that over to reading stuff
    from drm_display_info and if needed, push stuff into the core). Also,
    I can't come up with a good reason why DC needs all this (except to
    reimplement half of our edid quirk table, which really isn't a good
    idea). Might be good if you put this onto the list of things to fix
    long-term, but imo not a blocker. Definitely make sure new stuff
    doesn't slip in (i.e. if you start adding edid quirks to DC instead of
    the drm core, refactoring to use the core edid stuff was pointless)."
    ~ Daniel Vetter


11. Remove dc/i2caux. This folder can be somewhat misleading. It's basically an
overy complicated HW programming function for sendind and receiving i2c/aux
commands. We can greatly simplify that and move it into dc/dceXYZ like other
HW blocks.

12. drm_modeset_lock in MST should no longer be needed in recent kernels
    * Adopt appropriate locking scheme

13. get_modes and best_encoder callbacks look a bit funny. Can probably rip out
a few indirections, and consider removing entirely and using the
drm_atomic_helper_best_encoder default behaviour.

14. core/dc_debug.c, consider switching to the atomic state debug helpers and
moving all your driver state printing into the various atomic_print_state
callbacks. There's also plans to expose this stuff in a standard way across all
drivers, to make debugging userspace compositors easier across different hw.

15. Move DP/HDMI dual mode adaptors to drm_dp_dual_mode_helper.c. See
dal_ddc_service_i2c_query_dp_dual_mode_adaptor.

16. Move to core SCDC helpers (I think those are new since initial DC review).

17. There's still a pretty massive layer cake around dp aux and DPCD handling,
with like 3 levels of abstraction and using your own structures instead of the
stuff in drm_dp_helper.h. drm_dp_helper.h isn't really great and already has 2
incompatible styles, just means more reasons not to add a third (or well third
one gets to do the cleanup refactor).

18. There's a pile of sink handling code, both for DP and HDMI where I didn't
immediately recognize the standard. I think long term it'd be best for the drm
subsystem if we try to move as much of that into helpers/core as possible, and
share it with drivers. But that's a very long term goal, and by far not just an
issue with DC - other drivers, especially around DP sink handling, are equally
guilty.

19. DONE - The DC logger is still a rather sore thing, but I know that the
DRM_DEBUG stuff just isn't up to the challenges either. We need to figure out
something that integrates better with DRM and linux debug printing, while not
being useless with filtering output. dynamic debug printing might be an option.

20. Use kernel i2c device to program HDMI retimer. Some boards have an HDMI
retimer that we need to program to pass PHY compliance. Currently that's
bypassing the i2c device and goes directly to HW. This should be changed.

21. Remove vector.c from dc/basics. It's used in DDC code which can probably
be simplified enough to no longer need a vector implementation.