Re: [PATCH] drm/amd/display: invalidate DP CEC state on s3 suspend

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

Please run ./scripts/checkpatch.pl patch_file and fix reported errors 
and warnings. Thanks.

On 9/11/26 20:30, Dan Himebauch wrote:
> [You don't often get email from danielhimebauch@gmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> 
> HTPC setups on Linux with discrete GPUs can opt to use an active DP to
> HDMI adaptor in order to carry CEC over DP AUX, as most GPUs do not
> wire up CEC pin 13.
> 
> Currently under s3 suspend, amdgpu invalidates native HDMI CEC state
> but leaves DP AUX CEC physical address valid, which can leave these
> adapter's CEC states stale across suspend and make wake transmissions
> to fail before adapter is reconfigured.
> 
> This patch allows invalidating the DP AUX CEC physical address during
> suspend for AUX mode connectors. Normal connector detection reattaches
> adaptor using the physical address from EDID.
> 
> Tested on a 9070xt HTPC on steamOS and UGREEN DP to HDMI adapter on
> amd-staging-drm-next at d8ab7636160e20bf6a2ad69cd975f4d63319f1d4 where
> unmodified tree reproduced resume NACK, with this patch, multiple
> cycles succeeded with ImageViewOn and ActiveSource transmission, and
> intended behavior on wake was observed with cecd.
> 
> Assisted-by: LLM
> Signed-off-by: xXJSONDeruloXx <danielhimebauch@gmail.com>
> ---
>   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c    | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> index 0b446133edd8..919394778a25 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> @@ -372,10 +372,13 @@ void amdgpu_dm_s3_handle_hdmi_cec(struct
> drm_device *ddev, bool suspend)
>    continue;
> 
>    aconnector = to_amdgpu_dm_connector(connector);
> - if (suspend)
> + if (suspend) {
>    hdmi_cec_unset_edid(aconnector);
> - else
> + if (aconnector->dc_link && aconnector->dc_link->aux_mode)
> + drm_dp_cec_unset_edid(&aconnector->dm_dp_aux.aux);
> + } else {
>    amdgpu_dm_hdmi_cec_set_edid(aconnector);
> + }
>    }
>    drm_connector_list_iter_end(&conn_iter);
>   }
> --
> 2.50.1 (Apple Git-155)