Re: [PATCH 02/16] drm/i915/vrr: Avoid reading vrr.enable based on fixed_rr check

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

On Tue, Mar 18, 2025 at 01:05:26PM +0530, Ankit Nautiyal wrote:
> Currently, vrr.enable is intended only for variable refresh rate timings.
> At this point, we do not set fixed refresh rate timings, but the GOP can,
> which creates a problem during the readback of vrr.enable.
> 
> The GOP enables the VRR timing generator with fixed timings, while the
> driver only recognizes the VRR timing generator as enabled with
> variable timings. This discrepancy causes an issue due to the
> fixed refresh rate check during readback. Since the VRR timing generator
> is enabled and we do not support fixed timings, the readback should set
> vrr.enable so that the driver can disable the VRR timing generator.
> However, the current check does not allow this.
> 
> Therefore, remove the fixed refresh rate check during readback.
> 
> Fixes: 27217f9d1856 ("drm/i915/vrr: Track vrr.enable only for variable timing")
> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_vrr.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index aa65a6933ddb..6bdcdfed4b9b 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -657,8 +657,7 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
>  		}
>  	}
>  
> -	crtc_state->vrr.enable = trans_vrr_ctl & VRR_CTL_VRR_ENABLE &&
> -				 !intel_vrr_is_fixed_rr(crtc_state);
> +	crtc_state->vrr.enable = trans_vrr_ctl & VRR_CTL_VRR_ENABLE;

Doesn't this break the state checker when we use the VRR timing
generator for fixed refresh modes?

>  
>  	/*
>  	 * #TODO: For Both VRR and CMRR the flag I915_MODE_FLAG_VRR is set for mode_flags.
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel