Re: [Intel-gfx] [PATCH 2/4] drm/i915/mst: Disable transcoder before deleting the payload

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Oct 18, 2023 at 06:41:21PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Bspec tells us that we should disable the transcoder before
> deleting the payload. Looks like this has been reversed since
> MST support was added.

I suppose this shouldn't matter in practice since the downstream
device shouldn't really do anything with the new payload until
we send the ACT. But I see no compelling reason to deviate from
the bspec sequence regardless.

> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 7b4628f4f124..57eb581b8a50 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -587,10 +587,6 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
>  	struct intel_dp *intel_dp = &dig_port->dp;
>  	struct intel_connector *connector =
>  		to_intel_connector(old_conn_state->connector);
> -	struct drm_dp_mst_topology_state *new_mst_state =
> -		drm_atomic_get_new_mst_topology_state(&state->base, &intel_dp->mst_mgr);
> -	struct drm_dp_mst_atomic_payload *new_payload =
> -		drm_atomic_get_mst_payload_state(new_mst_state, connector->port);
>  	struct drm_i915_private *i915 = to_i915(connector->base.dev);
>  
>  	drm_dbg_kms(&i915->drm, "active links %d\n",
> @@ -598,8 +594,6 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
>  
>  	intel_hdcp_disable(intel_mst->connector);
>  
> -	drm_dp_remove_payload_part1(&intel_dp->mst_mgr, new_mst_state, new_payload);
> -
>  	intel_audio_codec_disable(encoder, old_crtc_state, old_conn_state);
>  }
>  
> @@ -634,6 +628,8 @@ static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
>  
>  	intel_disable_transcoder(old_crtc_state);
>  
> +	drm_dp_remove_payload_part1(&intel_dp->mst_mgr, new_mst_state, new_payload);
> +
>  	clear_act_sent(encoder, old_crtc_state);
>  
>  	intel_de_rmw(dev_priv, TRANS_DDI_FUNC_CTL(old_crtc_state->cpu_transcoder),
> -- 
> 2.41.0

-- 
Ville Syrjälä
Intel