Re: [PATCH v3 12/16] drm/i915/ddi: enable ACT handling for 128b/132b SST

[Imre Deak <imre.deak@intel.com>]

On Fri, Jan 03, 2025 at 03:52:35PM +0200, Jani Nikula wrote:
> Add ACT handling for 128b/132b SST enable/disable.
> 
> This is preparation for enabling 128b/132b SST. This path is not
> reachable yet.
> 
> v2:
> - Check for !is_hdmi (Imre)
> - Add disable sequence (Imre)
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 29 ++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index cdfb7caadcee..541e89cfc347 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3199,7 +3199,9 @@ static void intel_ddi_post_disable_hdmi_or_sst(struct intel_atomic_state *state,
>  {
>  	struct intel_display *display = to_intel_display(encoder);
>  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);

The above could've been scoped the same way as in intel_ddi_enable(),
but the patch looks ok:

Reviewed-by: Imre Deak <imre.deak@intel.com>

>  	struct intel_crtc *pipe_crtc;
> +	bool is_hdmi = intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_HDMI);
>  	int i;
>  
>  	for_each_pipe_crtc_modeset_disable(display, pipe_crtc, old_crtc_state, i) {
> @@ -3211,6 +3213,20 @@ static void intel_ddi_post_disable_hdmi_or_sst(struct intel_atomic_state *state,
>  
>  	intel_disable_transcoder(old_crtc_state);
>  
> +	/* 128b/132b SST */
> +	if (!is_hdmi && intel_dp_is_uhbr(old_crtc_state)) {
> +		/* VCPID 1, start slot 0 for 128b/132b, clear */
> +		drm_dp_dpcd_write_payload(&intel_dp->aux, 1, 0, 0);
> +
> +		intel_ddi_clear_act_sent(encoder, old_crtc_state);
> +
> +		intel_de_rmw(display, TRANS_DDI_FUNC_CTL(display, old_crtc_state->cpu_transcoder),
> +			     TRANS_DDI_DP_VC_PAYLOAD_ALLOC, 0);
> +
> +		intel_ddi_wait_for_act_sent(encoder, old_crtc_state);
> +		drm_dp_dpcd_poll_act_handled(&intel_dp->aux, 0);
> +	}
> +
>  	intel_ddi_disable_transcoder_func(old_crtc_state);
>  
>  	for_each_pipe_crtc_modeset_disable(display, pipe_crtc, old_crtc_state, i) {
> @@ -3493,6 +3509,19 @@ static void intel_ddi_enable(struct intel_atomic_state *state,
>  	/* Enable/Disable DP2.0 SDP split config before transcoder */
>  	intel_audio_sdp_split_update(crtc_state);
>  
> +	/* 128b/132b SST */
> +	if (!is_hdmi && intel_dp_is_uhbr(crtc_state)) {
> +		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> +
> +		intel_ddi_clear_act_sent(encoder, crtc_state);
> +
> +		intel_de_rmw(display, TRANS_DDI_FUNC_CTL(display, cpu_transcoder), 0,
> +			     TRANS_DDI_DP_VC_PAYLOAD_ALLOC);
> +
> +		intel_ddi_wait_for_act_sent(encoder, crtc_state);
> +		drm_dp_dpcd_poll_act_handled(&intel_dp->aux, 0);
> +	}
> +
>  	intel_enable_transcoder(crtc_state);
>  
>  	intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> -- 
> 2.39.5
>