[PATCH v2 08/13] drm/i915/vrr: Implement vblank evasion with DC balancing

[Nautiyal, Ankit K]

On 4/21/2025 9:18 PM, Mitul Golani wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Add vblank evasion logic when vrr is already enabled along with
> dc balance is computed.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>


> ---
>   drivers/gpu/drm/i915/display/intel_dsb.c    | 31 ++++++++++++++++++++-
>   drivers/gpu/drm/i915/display/intel_vblank.c | 26 +++++++++++++++--
>   2 files changed, 53 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
> index 72fe390c5af2..ffd10ee96e29 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -577,7 +577,36 @@ void intel_dsb_vblank_evade(struct intel_atomic_state *state,
>   	if (crtc_state->has_psr)
>   		intel_dsb_emit_wait_dsl(dsb, DSB_OPCODE_WAIT_DSL_OUT, 0, 0);
>   
> -	if (pre_commit_is_vrr_active(state, crtc)) {
> +	if (pre_commit_is_vrr_active(state, crtc) && crtc_state->vrr.dc_balance.enable) {
> +		int vblank_delay = intel_vrr_vblank_delay(crtc_state);
> +		int vmin_vblank_start, vmax_vblank_start;
> +
> +		vmin_vblank_start = intel_vrr_dcb_vmin_vblank_start_next(crtc_state);
> +
> +		if (vmin_vblank_start >= 0) {
> +			end = vmin_vblank_start;
> +			start = end - vblank_delay - latency;
> +			intel_dsb_wait_scanline_out(state, dsb, start, end);
> +		}
> +
> +		vmax_vblank_start = intel_vrr_dcb_vmax_vblank_start_next(crtc_state);
> +
> +		if (vmax_vblank_start >= 0) {
> +			end = vmax_vblank_start;
> +			start = end - vblank_delay - latency;
> +			intel_dsb_wait_scanline_out(state, dsb, start, end);
> +		}
> +
> +		vmin_vblank_start = intel_vrr_dcb_vmin_vblank_start_final(crtc_state);
> +		end = vmin_vblank_start;
> +		start = end - vblank_delay - latency;
> +		intel_dsb_wait_scanline_out(state, dsb, start, end);
> +
> +		vmax_vblank_start = intel_vrr_dcb_vmax_vblank_start_final(crtc_state);
> +		end = vmax_vblank_start;
> +		start = end - vblank_delay - latency;
> +		intel_dsb_wait_scanline_out(state, dsb, start, end);
> +	} else if (pre_commit_is_vrr_active(state, crtc)) {
>   		int vblank_delay = intel_vrr_vblank_delay(crtc_state);
>   
>   		end = intel_vrr_vmin_vblank_start(crtc_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c b/drivers/gpu/drm/i915/display/intel_vblank.c
> index 680013f00fc0..eb74d08d6690 100644
> --- a/drivers/gpu/drm/i915/display/intel_vblank.c
> +++ b/drivers/gpu/drm/i915/display/intel_vblank.c
> @@ -644,10 +644,30 @@ intel_pre_commit_crtc_state(struct intel_atomic_state *state,
>   
>   static int vrr_vblank_start(const struct intel_crtc_state *crtc_state)
>   {
> -	if (intel_vrr_is_push_sent(crtc_state))
> -		return intel_vrr_vmin_vblank_start(crtc_state);
> +	bool is_push_sent = intel_vrr_is_push_sent(crtc_state);
> +	int vblank_start;
> +
> +	if (!crtc_state->vrr.dc_balance.enable) {
> +		if (is_push_sent)
> +			return intel_vrr_vmin_vblank_start(crtc_state);
> +		else
> +			return intel_vrr_vmax_vblank_start(crtc_state);
> +	}
> +
> +	if (is_push_sent)
> +		vblank_start = intel_vrr_dcb_vmin_vblank_start_next(crtc_state);
>   	else
> -		return intel_vrr_vmax_vblank_start(crtc_state);
> +		vblank_start = intel_vrr_dcb_vmax_vblank_start_next(crtc_state);
> +
> +	if (vblank_start >= 0)
> +		return vblank_start;
> +
> +	if (is_push_sent)
> +		vblank_start = intel_vrr_dcb_vmin_vblank_start_final(crtc_state);
> +	else
> +		vblank_start = intel_vrr_dcb_vmax_vblank_start_final(crtc_state);
> +
> +	return vblank_start;
>   }
>   
>   void intel_vblank_evade_init(const struct intel_crtc_state *old_crtc_state,