Re: [PATCH v10 04/17] drm/i915/vrr: Add functions to read out vmin/vmax stuff

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 12/2/2025 1:06 PM, Mitul Golani wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Calculate delayed vblank start position with the help of added
> vmin/vmax stuff for next frame and final computation.
>
> --v2:
> - Correct Author details.
>
> --v3:
> - Separate register details from this  patch.
>
> --v4:
> - Add mask macros.
>
> --v5:
> - As live prefix params indicate timings for current frame,
> read just _live prefix values instead of next frame timings as
> done previously.
> - Squash Refactor vrr params patch.
>
> --v6:
> - Use error code while returning invalid values. (Jani, Nikula)
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>

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


> ---
>   drivers/gpu/drm/i915/display/intel_vrr.c | 56 ++++++++++++++++++++++++
>   drivers/gpu/drm/i915/display/intel_vrr.h |  5 +++
>   2 files changed, 61 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index b92c42fde937..31f3a7b6e00d 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -261,6 +261,12 @@ static int intel_vrr_hw_value(const struct intel_crtc_state *crtc_state,
>   		return value - crtc_state->set_context_latency;
>   }
>   
> +static int intel_vrr_vblank_start(const struct intel_crtc_state *crtc_state,
> +				  int vmin_vmax)
> +{
> +	return intel_vrr_hw_value(crtc_state, vmin_vmax) - crtc_state->vrr.guardband;
> +}
> +
>   /*
>    * For fixed refresh rate mode Vmin, Vmax and Flipline all are set to
>    * Vtotal value.
> @@ -898,3 +904,53 @@ int intel_vrr_vmin_safe_window_end(const struct intel_crtc_state *crtc_state)
>   	return intel_vrr_vmin_vblank_start(crtc_state) -
>   	       crtc_state->set_context_latency;
>   }
> +
> +int intel_vrr_dcb_vmin_vblank_start_next(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	u32 tmp = 0;
> +
> +	tmp = intel_de_read(display, TRANS_VRR_DCB_ADJ_FLIPLINE_CFG_LIVE(cpu_transcoder));
> +
> +	if (REG_FIELD_GET(VRR_DCB_ADJ_FLIPLINE_CNT_MASK, tmp) == 0)
> +		return -EINVAL;
> +
> +	return intel_vrr_vblank_start(crtc_state, VRR_DCB_ADJ_FLIPLINE(tmp) + 1);
> +}
> +
> +int intel_vrr_dcb_vmax_vblank_start_next(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	u32 tmp = 0;
> +
> +	tmp = intel_de_read(display, TRANS_VRR_DCB_ADJ_VMAX_CFG_LIVE(cpu_transcoder));
> +
> +	if (REG_FIELD_GET(VRR_DCB_ADJ_VMAX_CNT_MASK, tmp) == 0)
> +		return -EINVAL;
> +
> +	return intel_vrr_vblank_start(crtc_state, VRR_DCB_ADJ_VMAX(tmp) + 1);
> +}
> +
> +int intel_vrr_dcb_vmin_vblank_start_final(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	u32 tmp = 0;
> +
> +	tmp = intel_de_read(display, TRANS_VRR_DCB_FLIPLINE_LIVE(cpu_transcoder));
> +
> +	return intel_vrr_vblank_start(crtc_state, VRR_DCB_FLIPLINE(tmp) + 1);
> +}
> +
> +int intel_vrr_dcb_vmax_vblank_start_final(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	u32 tmp = 0;
> +
> +	tmp = intel_de_read(display, TRANS_VRR_DCB_VMAX_LIVE(cpu_transcoder));
> +
> +	return intel_vrr_vblank_start(crtc_state, VRR_DCB_VMAX(tmp) + 1);
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
> index bc9044621635..66fb9ad846f2 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.h
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.h
> @@ -43,4 +43,9 @@ bool intel_vrr_always_use_vrr_tg(struct intel_display *display);
>   int intel_vrr_safe_window_start(const struct intel_crtc_state *crtc_state);
>   int intel_vrr_vmin_safe_window_end(const struct intel_crtc_state *crtc_state);
>   
> +int intel_vrr_dcb_vmin_vblank_start_next(const struct intel_crtc_state *crtc_state);
> +int intel_vrr_dcb_vmax_vblank_start_next(const struct intel_crtc_state *crtc_state);
> +int intel_vrr_dcb_vmin_vblank_start_final(const struct intel_crtc_state *crtc_state);
> +int intel_vrr_dcb_vmax_vblank_start_final(const struct intel_crtc_state *crtc_state);
> +
>   #endif /* __INTEL_VRR_H__ */