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

Harry Wentland harry.wentland at amd.com
Mon Aug 11 21:26:28 UTC 2025 


On 2025-08-11 17:09, Limonciello, Mario wrote:
> 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

DC should stay OS-agnostic. No DRM concepts in DC please.

Why the need to change dc_edid_is_same_edid?

I'll comment directly on the patch.

Harry

>>
>> 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
>>>>>
>>>>
>>>
>>
>

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