Re: [PATCH 07/19] drm/i915/vrr: Prepare for fixed refresh rate timings

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

On Fri, Feb 14, 2025 at 05:41:17PM +0530, Ankit Nautiyal wrote:
> Currently we always compute the timings as if vrr is enabled.
> With this approach the state checker becomes complicated when we
> introduce fixed refresh rate mode with vrr timing generator.
> 
> To avoid the complications, instead of always computing vrr timings, we
> compute vrr timings based on uapi.vrr_enable knob.
> So when the knob is disabled we always compute vmin=flipline=vmax.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_vrr.c | 54 ++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 3bcf2a026ad3..a4ed102a2119 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -263,6 +263,35 @@ int intel_vrr_fixed_rr_vtotal(const struct intel_crtc_state *crtc_state)
>  			intel_vrr_real_vblank_delay(crtc_state);
>  }
>  
> +static
> +int intel_vrr_fixed_rr_vmax(const struct intel_crtc_state *crtc_state)
> +{
> +	return intel_vrr_fixed_rr_vtotal(crtc_state);
> +}
> +
> +static
> +int intel_vrr_fixed_rr_vmin(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +
> +	return intel_vrr_fixed_rr_vtotal(crtc_state) -
> +		intel_vrr_flipline_offset(display);
> +}
> +
> +static
> +int intel_vrr_fixed_rr_flipline(const struct intel_crtc_state *crtc_state)
> +{
> +	return intel_vrr_fixed_rr_vtotal(crtc_state);
> +}
> +
> +static
> +void intel_vrr_prepare_fixed_timings(struct intel_crtc_state *crtc_state)
> +{
> +	crtc_state->vrr.vmax = intel_vrr_fixed_rr_vmax(crtc_state);
> +	crtc_state->vrr.vmin = intel_vrr_fixed_rr_vmin(crtc_state);
> +	crtc_state->vrr.flipline = intel_vrr_fixed_rr_flipline(crtc_state);

Same comment as to the previous patch: vblank delay is not a thing
at this point, so this needs to just use the actual timings without
any adjustments.

The rest of the patch looks fine.

> +}
> +
>  static
>  int intel_vrr_compute_vmin(struct intel_crtc_state *crtc_state)
>  {
> @@ -343,6 +372,8 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
>  		intel_vrr_compute_vrr_timings(crtc_state);
>  	else if (is_cmrr_frac_required(crtc_state) && is_edp)
>  		intel_vrr_compute_cmrr_timings(crtc_state);
> +	else
> +		intel_vrr_prepare_fixed_timings(crtc_state);
>  
>  	if (HAS_AS_SDP(display)) {
>  		crtc_state->vrr.vsync_start =
> @@ -514,6 +545,13 @@ void intel_vrr_enable(const struct intel_crtc_state *crtc_state)
>  	if (!crtc_state->vrr.enable)
>  		return;
>  
> +	intel_de_write(display, TRANS_VRR_VMIN(display, cpu_transcoder),
> +		       crtc_state->vrr.vmin - 1);
> +	intel_de_write(display, TRANS_VRR_VMAX(display, cpu_transcoder),
> +		       crtc_state->vrr.vmax - 1);
> +	intel_de_write(display, TRANS_VRR_FLIPLINE(display, cpu_transcoder),
> +		       crtc_state->vrr.flipline - 1);
> +
>  	intel_de_write(display, TRANS_PUSH(display, cpu_transcoder),
>  		       TRANS_PUSH_EN);
>  
> @@ -527,6 +565,20 @@ void intel_vrr_enable(const struct intel_crtc_state *crtc_state)
>  	}
>  }
>  
> +static
> +void intel_vrr_set_fixed_rr_timings(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +
> +	intel_de_write(display, TRANS_VRR_VMIN(display, cpu_transcoder),
> +		       intel_vrr_fixed_rr_vmin(crtc_state) - 1);
> +	intel_de_write(display, TRANS_VRR_VMAX(display, cpu_transcoder),
> +		       intel_vrr_fixed_rr_vmax(crtc_state) - 1);
> +	intel_de_write(display, TRANS_VRR_FLIPLINE(display, cpu_transcoder),
> +		       intel_vrr_fixed_rr_flipline(crtc_state) - 1);
> +}
> +
>  void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
>  {
>  	struct intel_display *display = to_intel_display(old_crtc_state);
> @@ -541,6 +593,8 @@ void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
>  				TRANS_VRR_STATUS(display, cpu_transcoder),
>  				VRR_STATUS_VRR_EN_LIVE, 1000);
>  	intel_de_write(display, TRANS_PUSH(display, cpu_transcoder), 0);
> +
> +	intel_vrr_set_fixed_rr_timings(old_crtc_state);
>  }
>  
>  static
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel