[PATCH v3 00/14] drm/amd/display: more drm_edid to AMD display driver

[Melissa Wen]

Hi,

Siqueira and I have been working on a solution to reduce the usage of
drm_edid_raw in the AMD display driver, since the current guideline in
the DRM subsystem is to stop handling raw edid data in driver-specific
implementation and use opaque `drm_edid` object with common-code
helpers.

In short, this series approaches the issue of maintaining DC as an
OS-agnostic component by creating a mid layer to isolate `drm_edid`
helpers that need to be called in the DC code, while allowing other OSes
to implement their specific implementation. This is an extension of [1].

- Patch 1 addresses a possible leak added by previous migration to
  drm_edid.
- Patch 2 allocates a temporary drm_edid from raw edid for parsing.
- Patches 3-7 use common-code, drm_edid helpers to parse edid
  capabilities instead of driver-specific solutions. For this, patch 4
  introduces a new helper that gets monitor name from drm_edid.
- Patches 8-9 are groundwork to reduce the noise of Linux/DRM specific
  code in the DC shared code
- Patch 10 creates a mid layer to make DC embraces different ways of
  handling EDID by platforms.
- Patch 11 move open-coded management of raw EDID data to the mid
  layer created before.
- Patch 12 introduces a helper that compares EDIDs from two drm_edids.
- Patch 13 adds drm_edid to dc_sink struct and a mid-layer helper to
  free `drm_edid`.
- Patch 14 switch dc_edid to drm_edid across the driver in a way that
  the DC shared code is little affected by Linux specific stuff.

[v1] https://lore.kernel.org/dri-devel/20250411201333.151335-1-mwen@igalia.com/
Changes:
- fix broken approach to get monitor name from eld (Jani)
  - I introduced a new helper that gets monitor name from drm_edid
- rename drm_edid_eq to drm_edid_eq_buf and doc fixes (Jani)
- add NULL edid checks (Jani)
- fix mishandling of product_id.manufacturer_name (Michel)
  - I directly set it to manufacturer_id since sparse didn't complain.
- add Mario's r-b in the first fix patch and fix commit msg typo.

[v2] https://lore.kernel.org/dri-devel/20250507001712.120215-1-mwen@igalia.com/
Changes:
- kernel-doc and commit msg fixes (Jani)
- use drm_edid_legacy_init instead of open coded (Jani)
- place drm_edid new func into the right section (Jani)
- paramenter names fix (Jani)
- add Jani's r-b to the patch 12
- remove unnecessary include (Jani)
- call dc_edid_sink_edid_free in link_detection, instead of drm_edid_free
- rebase on top of asdn

---

There are three specific points where we still use drm_edid_raw() in the
driver:
1. raw edid data for write EDID checksum in DP_TEST_EDID_CHECKSUM via
   drm_dp_dpcd_write(), that AFAIK there is no common code solution yet;
2. open-coded connectivity log for dc link detection, that maybe can be
   moved to drm (?);
3. open-coded parser that I suspect is a lot of duplicated code, but
   needs careful examining.

I suggest to address those points in a next phase for regression control.

Finally, I'm not sure amdgpu_dm/dc_edid is the right place and file name
for the mid-layer. Suggestions?

[1] https://lore.kernel.org/amd-gfx/20250308142650.35920-1-mwen@igalia.com/

Let me know yours thoughts!

Melissa

Melissa Wen (12):
  drm/amd/display: make sure drm_edid stored in aconnector doesn't leak
  drm/amd/display: start using drm_edid helpers to parse EDID caps
  drm/amd/display: use drm_edid_product_id for parsing EDID product info
  drm/edid: introduce a helper that gets monitor name from drm_edid
  drm/amd/display: get panel id with drm_edid helper
  drm/amd/display: get SAD from drm_eld when parsing EDID caps
  drm/amd/display: get SADB from drm_eld when parsing EDID caps
  drm/amd/display: simplify dm_helpers_parse_edid_caps signature
  drm/amd/display: change DC functions to accept private types for edid
  drm/edid: introduce a helper that compares edid data from two drm_edid
  drm/amd/display: add drm_edid to dc_sink
  drm/amd/display: move dc_sink from dc_edid to drm_edid

Rodrigo Siqueira (2):
  drm/amd/display: add a mid-layer file to handle EDID in DC
  drm/amd/display: create a function to fill dc_sink with edid data

 .../gpu/drm/amd/display/amdgpu_dm/Makefile    |  1 +
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 33 +++----
 .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 97 ++++++++-----------
 .../display/amdgpu_dm/amdgpu_dm_mst_types.c   | 21 ++--
 .../gpu/drm/amd/display/amdgpu_dm/dc_edid.c   | 33 +++++++
 .../gpu/drm/amd/display/amdgpu_dm/dc_edid.h   | 15 +++
 .../drm/amd/display/dc/core/dc_link_exports.c |  9 +-
 drivers/gpu/drm/amd/display/dc/core/dc_sink.c |  3 +
 drivers/gpu/drm/amd/display/dc/dc.h           | 10 +-
 drivers/gpu/drm/amd/display/dc/dm_helpers.h   |  7 +-
 drivers/gpu/drm/amd/display/dc/inc/link.h     |  9 +-
 .../drm/amd/display/dc/link/link_detection.c  | 30 ++----
 .../drm/amd/display/dc/link/link_detection.h  |  9 +-
 drivers/gpu/drm/bridge/sil-sii8620.c          |  2 +-
 drivers/gpu/drm/display/drm_dp_mst_topology.c |  2 +-
 drivers/gpu/drm/drm_edid.c                    | 54 ++++++++---
 include/drm/drm_edid.h                        | 10 +-
 17 files changed, 189 insertions(+), 156 deletions(-)
 create mode 100644 drivers/gpu/drm/amd/display/amdgpu_dm/dc_edid.c
 create mode 100644 drivers/gpu/drm/amd/display/amdgpu_dm/dc_edid.h

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2.47.2