Re: [PATCH 06/28] drm/i915/vrr: Fill VRR timing generator mode for CMRR and VRR

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

On Mon, Feb 03, 2025 at 06:08:18PM +0530, Ankit Nautiyal wrote:
> Fill vrr.mode during compute_config and update intel_vrr_get_config() to
> read vrr.mode based on CMRR and VRR enable conditions.

This vrr.mode thing still feels like a bit of a distraction at this
point in the series. If we canskip this stuff for now I think we
should be able to get this done more simply. 

The other thing that seems to complicate things is the attempt at doing
something to intel_crtc_update_active_timings(). I think it'll be
easier to just essentially pretend that things are running with the
legacy timing generator when using fixed refresh rate. That way 
we don't have to touch intel_crtc_update_active_timings() at all.

So basically just:
- add the vmin/vmax/flipline reprogramming to vrr_disable() and vrr_enable()
- make the timing generator enable/disable optional in those places
- add the stuff to the modeset sequence to program the initial
  timings (ie. fixed timings) and enable/disable the timing generator
- also update to the new fixed timings in intel_set_transcoder_timings_lrr()
- adjust readout to not set vrr.enable when vmax==vmin_flipline

I think that should work perfectly fine for adl+. icl/tgl will be
slightly wrong due to the weird extra scanline delay after
vactive, but I don't think we should really have to care about that
since we aren't going to enable this on those platforms anyway.

> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 1 +
>  drivers/gpu/drm/i915/display/intel_vrr.c     | 5 +++++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index a6383ddde871..9cff080d4ff9 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5803,6 +5803,7 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
>  
>  	if (!fastset) {
>  		PIPE_CONF_CHECK_BOOL(vrr.enable);
> +		PIPE_CONF_CHECK_X(vrr.mode);
>  		PIPE_CONF_CHECK_I(vrr.vmin);
>  		PIPE_CONF_CHECK_I(vrr.vmax);
>  		PIPE_CONF_CHECK_I(vrr.flipline);
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 6f314e209e96..ded5466c5214 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -227,6 +227,7 @@ void intel_vrr_compute_cmrr_timings(struct intel_crtc_state *crtc_state)
>  {
>  	crtc_state->vrr.enable = true;
>  	crtc_state->cmrr.enable = true;
> +	crtc_state->vrr.mode = INTEL_VRRTG_MODE_CMRR;
>  	/*
>  	 * TODO: Compute precise target refresh rate to determine
>  	 * if video_mode_required should be true. Currently set to
> @@ -243,6 +244,7 @@ static
>  void intel_vrr_compute_vrr_timings(struct intel_crtc_state *crtc_state)
>  {
>  	crtc_state->vrr.enable = true;
> +	crtc_state->vrr.mode = INTEL_VRRTG_MODE_VRR;
>  	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
>  }
>  
> @@ -506,12 +508,15 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
>  
>  	if (HAS_CMRR(display) && trans_vrr_ctl & VRR_CTL_CMRR_ENABLE) {
>  		crtc_state->cmrr.enable = true;
> +		crtc_state->vrr.mode = INTEL_VRRTG_MODE_CMRR;
>  		crtc_state->cmrr.cmrr_n =
>  			intel_de_read64_2x32(display, TRANS_CMRR_N_LO(display, cpu_transcoder),
>  					     TRANS_CMRR_N_HI(display, cpu_transcoder));
>  		crtc_state->cmrr.cmrr_m =
>  			intel_de_read64_2x32(display, TRANS_CMRR_M_LO(display, cpu_transcoder),
>  					     TRANS_CMRR_M_HI(display, cpu_transcoder));
> +	} else if (trans_vrr_ctl & VRR_CTL_VRR_ENABLE) {
> +		crtc_state->vrr.mode = INTEL_VRRTG_MODE_VRR;
>  	}
>  
>  	if (DISPLAY_VER(display) >= 13)
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel