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

Mon Aug 11 21:09:54 UTC 2025

On 8/11/25 4:08 PM, Hung, Alex wrote:
> Melissa,
> 
> The patchset passed promotion and CI.
> 
> However, since our DC code is shared with the other OS, calling drm_* 
> functions in DC won't work for us. For example, calling 
> dc_edid_copy_edid_to_sink from dc/link/link_detection.c in patch 14.
> 
> I don't have a good way to handle it. Does it make sense not to touch DC 
> code for now?

What about if we have a set of compatibility macros in DC code?

Something like this:

#ifndef drm_dbg
#define drm_dbg ....
#endif
> 
> On 8/11/25 13:40, Melissa Wen wrote:
>>
>>
>> On 28/07/2025 20:29, Alex Hung wrote:
>>> Thanks. I will send v6 to promotion test.
>> Hi Alex,
>>
>> Any news about this round of tests?
>>
>> BR,
>>
>> Melissa
>>
>>>
>>> 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 at 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 at 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 at 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 at 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 at 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 at 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
>>>>
>>>
>>
> 