Re: [PATCH 11/20] drm/i915: prepare scaler for YCBCR420 modeset

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

On Mon, Jul 10, 2017 at 04:48:39PM +0530, Shashank Sharma wrote:
> To get a YCBCR420 output from intel platforms, we need one
> scaler to scale down YCBCR444 samples to YCBCR420 samples.
> 
> This patch:
> - Does scaler allocation for HDMI ycbcr420 outputs.
> - Programs PIPE_MISC register for ycbcr420 output.
> - Adds a new scaler user "HDMI output" to plug-into existing
>   scaler framework. This output type is identified using bit
>   30 of the scaler users bitmap.
> 
> V2: rebase
> V3: rebase
> V4: rebase
> V5: addressed review comments from Ander:
>     - No need to check both scaler_user && hdmi_output.
>       Check for scaler_user is enough.
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_atomic.c  |  6 ++++++
>  drivers/gpu/drm/i915/intel_display.c | 23 +++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h     | 10 +++++++++-
>  drivers/gpu/drm/i915/intel_hdmi.c    | 12 ++++++++++++
>  drivers/gpu/drm/i915/intel_panel.c   |  3 ++-
>  5 files changed, 52 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
> index 36d4e63..040d111 100644
> --- a/drivers/gpu/drm/i915/intel_atomic.c
> +++ b/drivers/gpu/drm/i915/intel_atomic.c
> @@ -264,6 +264,12 @@ int intel_atomic_setup_scalers(struct drm_i915_private *dev_priv,
>  
>  			/* panel fitter case: assign as a crtc scaler */
>  			scaler_id = &scaler_state->scaler_id;
> +		} else if (i == SKL_420_OUTPUT_INDEX) {

I think Ander already said that we should just tie this into the normal
pfit pipe scaler user. I agree. Having to users doesn't actually make
sense because there can be only one pipe scaler, and if we want to do
scaled 4:2:0 output then we anyway need to handle both cases
simultaneosly.

> +			name = "YCBCR420-OUTPUT";
> +			idx = intel_crtc->base.base.id;
> +
> +			/* YCBCR420 case: needs a pipe scaler */
> +			scaler_id = &scaler_state->scaler_id;
>  		} else {
>  			name = "PLANE";
>  
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 01900e1..c56081e 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4621,6 +4621,9 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
>  	 */
>  	need_scaling = src_w != dst_w || src_h != dst_h;
>  
> +	if (scaler_user == SKL_420_OUTPUT_INDEX)
> +		need_scaling = true;
> +
>  	/*
>  	 * if plane is being disabled or scaler is no more required or force detach
>  	 *  - free scaler binded to this plane/crtc
> @@ -4668,6 +4671,26 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
>  }
>  
>  /**
> + * skl_update_scaler_crtc_420_output - Stages update to scaler state
> + * for YCBCR420 which needs a scaler, for downsampling.
> + *
> + * @state: crtc's scaler state
> + *
> + * Return
> + *     0 - scaler_usage updated successfully
> + *    error - requested scaling cannot be supported or other error condition
> + */
> +int skl_update_scaler_crtc_420_output(struct intel_crtc_state *state)
> +{
> +	const struct drm_display_mode *mode = &state->base.adjusted_mode;
> +
> +	return skl_update_scaler(state, !state->base.active,
> +		SKL_420_OUTPUT_INDEX, &state->scaler_state.scaler_id,
> +		state->pipe_src_w, state->pipe_src_h,
> +		mode->crtc_hdisplay, mode->crtc_vdisplay);
> +}
> +
> +/**
>   * skl_update_scaler_crtc - Stages update to scaler state for a given crtc.
>   *
>   * @state: crtc's scaler state
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 592243b..68b4fba 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -471,7 +471,8 @@ struct intel_crtc_scaler_state {
>  	 *
>  	 *     If a bit is set, a user is using a scaler.
>  	 *     Here user can be a plane or crtc as defined below:
> -	 *       bits 0-30 - plane (bit position is index from drm_plane_index)
> +	 *       bits 0-29 - plane (bit position is index from drm_plane_index)
> +	 *       bit 30    - hdmi output
>  	 *       bit 31    - crtc
>  	 *
>  	 * Instead of creating a new index to cover planes and crtc, using
> @@ -484,6 +485,12 @@ struct intel_crtc_scaler_state {
>  	 * avilability.
>  	 */
>  #define SKL_CRTC_INDEX 31
> +
> +	/*
> +	 * YCBCR 420 output consume a scaler. So adding a user
> +	 * for 420 output requirement.
> +	 */
> +#define SKL_420_OUTPUT_INDEX 30
>  	unsigned scaler_users;
>  
>  	/* scaler used by crtc for panel fitting purpose */
> @@ -1483,6 +1490,7 @@ void intel_mode_from_pipe_config(struct drm_display_mode *mode,
>  				 struct intel_crtc_state *pipe_config);
>  
>  int skl_update_scaler_crtc(struct intel_crtc_state *crtc_state);
> +int skl_update_scaler_crtc_420_output(struct intel_crtc_state *state);
>  int skl_max_scale(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state);
>  
>  static inline u32 intel_plane_ggtt_offset(const struct intel_plane_state *state)
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 276d916..9e8d784 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1355,6 +1355,7 @@ intel_hdmi_ycbcr420_config(struct drm_connector *connector,
>  			       struct intel_crtc_state *config,
>  			       int *clock_12bpc, int *clock_8bpc)
>  {
> +	struct intel_crtc *intel_crtc = to_intel_crtc(config->base.crtc);
>  
>  	if (!connector->ycbcr_420_allowed) {
>  		DRM_ERROR("Platform doesn't support YCBCR420 output\n");
> @@ -1366,6 +1367,17 @@ intel_hdmi_ycbcr420_config(struct drm_connector *connector,
>  	*clock_12bpc /= 2;
>  	*clock_8bpc /= 2;
>  	config->ycbcr420 = true;
> +
> +	/* YCBCR 420 output conversion needs a scaler */
> +	if (skl_update_scaler_crtc_420_output(config)) {
> +		DRM_ERROR("Scaler allocation for output failed\n");
> +		return false;
> +	}
> +
> +	/* Bind this scaler to pipe */
> +	intel_pch_panel_fitting(intel_crtc, config,
> +				DRM_MODE_SCALE_FULLSCREEN);
> +
>  	return true;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index 96c2cbd..fd2e081 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -110,7 +110,8 @@ intel_pch_panel_fitting(struct intel_crtc *intel_crtc,
>  
>  	/* Native modes don't need fitting */
>  	if (adjusted_mode->crtc_hdisplay == pipe_config->pipe_src_w &&
> -	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h)
> +	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h &&
> +	    !pipe_config->ycbcr420)
>  		goto done;
>  
>  	switch (fitting_mode) {
> -- 
> 2.7.4
> 
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-- 
Ville Syrjälä
Intel OTC
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