[PATCH] drm/amd/display: fix ABM disablement

[Hamza Mahfooz]

On 11/22/23 17:24, Hamza Mahfooz wrote:
> On recent versions of DMUB firmware, if we want to completely disable
> ABM we have to pass ABM_LEVEL_IMMEDIATE_DISABLE as the requested ABM
> level to DMUB. Otherwise, LCD eDP displays are unable to reach their
> maximum brightness levels. So, to fix this whenever the user requests an
> ABM level of 0 pass ABM_LEVEL_IMMEDIATE_DISABLE to DMUB instead. Also,
> to keep the user's experience consistent map ABM_LEVEL_IMMEDIATE_DISABLE
> to 0 when a user tries to read the requested ABM level.
> 
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz at amd.com>

Cc: stable at vger.kernel.org # 6.1+

> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 5d9496db0ecb..8cb92d941cd9 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -6230,7 +6230,7 @@ int amdgpu_dm_connector_atomic_set_property(struct drm_connector *connector,
>   		dm_new_state->underscan_enable = val;
>   		ret = 0;
>   	} else if (property == adev->mode_info.abm_level_property) {
> -		dm_new_state->abm_level = val;
> +		dm_new_state->abm_level = val ?: ABM_LEVEL_IMMEDIATE_DISABLE;
>   		ret = 0;
>   	}
>   
> @@ -6275,7 +6275,8 @@ int amdgpu_dm_connector_atomic_get_property(struct drm_connector *connector,
>   		*val = dm_state->underscan_enable;
>   		ret = 0;
>   	} else if (property == adev->mode_info.abm_level_property) {
> -		*val = dm_state->abm_level;
> +		*val = (dm_state->abm_level != ABM_LEVEL_IMMEDIATE_DISABLE) ?
> +			dm_state->abm_level : 0;
>   		ret = 0;
>   	}
>   
> @@ -6348,7 +6349,8 @@ void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector)
>   		state->pbn = 0;
>   
>   		if (connector->connector_type == DRM_MODE_CONNECTOR_eDP)
> -			state->abm_level = amdgpu_dm_abm_level;
> +			state->abm_level = amdgpu_dm_abm_level ?:
> +				ABM_LEVEL_IMMEDIATE_DISABLE;
>   
>   		__drm_atomic_helper_connector_reset(connector, &state->base);
>   	}
-- 
Hamza