From 31c0ed90b978f9fe99d48dc4a624ed0fe0dc21b7 Mon Sep 17 00:00:00 2001 From: Bhawanpreet Lakha Date: Thu, 26 Sep 2019 17:44:50 -0400 Subject: [PATCH] drm/amd/display: Add comments to hdcp property change code [Why] These comments are helpful in understanding which case each if statement handles. [How] Add comments for state transitions (9 possible cases) Signed-off-by: Bhawanpreet Lakha Reviewed-by: Zhan Liu Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 26 +++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 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 9df92c6..936979c 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -7238,26 +7238,35 @@ static bool is_content_protection_different(struct drm_connector_state *state, struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector); struct dm_connector_state *dm_con_state = to_dm_connector_state(connector->state); + /* Handle: Type0/1 change */ if (old_state->hdcp_content_type != state->hdcp_content_type && state->content_protection != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) { state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED; return true; } - /* CP is being re enabled, ignore this */ + /* CP is being re enabled, ignore this + * + * Handles: ENABLED -> DESIRED + */ if (old_state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED && state->content_protection == DRM_MODE_CONTENT_PROTECTION_DESIRED) { state->content_protection = DRM_MODE_CONTENT_PROTECTION_ENABLED; return false; } - /* S3 resume case, since old state will always be 0 (UNDESIRED) and the restored state will be ENABLED */ + /* S3 resume case, since old state will always be 0 (UNDESIRED) and the restored state will be ENABLED + * + * Handles: UNDESIRED -> ENABLED + */ if (old_state->content_protection == DRM_MODE_CONTENT_PROTECTION_UNDESIRED && state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED) state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED; /* Check if something is connected/enabled, otherwise we start hdcp but nothing is connected/enabled * hot-plug, headless s3, dpms + * + * Handles: DESIRED -> DESIRED (Special case) */ if (dm_con_state->update_hdcp && state->content_protection == DRM_MODE_CONTENT_PROTECTION_DESIRED && connector->dpms == DRM_MODE_DPMS_ON && aconnector->dc_sink != NULL) { @@ -7265,12 +7274,25 @@ static bool is_content_protection_different(struct drm_connector_state *state, return true; } + /* + * Handles: UNDESIRED -> UNDESIRED + * DESIRED -> DESIRED + * ENABLED -> ENABLED + */ if (old_state->content_protection == state->content_protection) return false; + /* + * Handles: UNDESIRED -> DESIRED + * DESIRED -> UNDESIRED + * ENABLED -> UNDESIRED + */ if (state->content_protection != DRM_MODE_CONTENT_PROTECTION_ENABLED) return true; + /* + * Handles: DESIRED -> ENABLED + */ return false; } -- 2.7.4