Re: [PATCH v6 00/14] drm/amd/display: more drm_edid to AMD display driver

[Alex Hung <alex.hung@amd.com>]

Thanks. I will send v6 to promotion test.

On 7/25/25 18:33, Melissa Wen wrote:
> 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.
> 
> To keep DC as an OS-agnostic component, we create a mid layer that
> isolates `drm_edid` helpers called in the DC code, while allowing other
> OSes to implement their specific implementation.
> 
> This work 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
> 
> [v3] https://lore.kernel.org/dri-devel/20250514202130.291324-1-mwen@igalia.com/
> Changes:
> - rebase to asdn
> - some kernel-doc fixes
> - move some changes to the right commit
> 
> [v4] https://lore.kernel.org/amd-gfx/20250613150015.245917-1-mwen@igalia.com/
> Changes:
> - fix comments and commit messages (Mario)
> - remove unnecessary drm_edid dup and fix mem leak (Mario)
> - add Mario's rb to patches 5-7
> 
> [v5] https://lore.kernel.org/amd-gfx/20250618152216.948406-1-mwen@igalia.com/
> Changes:
> - fix NULL pointer dereference (Alex H.) with the same approach proposed
>    by 7c3be3ce3dfae
> 
 > --->
> 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.
> 
> [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 | 109 +++++++-----------
>   .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  21 ++--
>   .../gpu/drm/amd/display/amdgpu_dm/dc_edid.c   |  39 +++++++
>   .../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, 199 insertions(+), 164 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
>