[PATCH v7 06/18] drm/i915/vrr: Add DC Balance params to crtc_state

[Jani Nikula]

On Tue, 24 Jun 2025, Mitul Golani <mitulkumar.ajitkumar.golani at intel.com> wrote:
> Add DC Balance params to crtc_state, also add state checker
> params for related properties.
>
> --v3:
> - Seggregate crtc_state params with this patch. (Ankit)
>
> --v4:
> - Update commit message and header. (Ankit)
> - Add +1 to VMIN and VMAX only when it is non-zero. (Ankit)
>
> 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_display.c  |  7 ++++++
>  .../drm/i915/display/intel_display_types.h    |  7 ++++++
>  drivers/gpu/drm/i915/display/intel_vrr.c      | 22 +++++++++++++++++++
>  3 files changed, 36 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index de8bf292897c..939366ecea85 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5429,6 +5429,13 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
>  		PIPE_CONF_CHECK_LLI(cmrr.cmrr_m);
>  		PIPE_CONF_CHECK_LLI(cmrr.cmrr_n);
>  		PIPE_CONF_CHECK_BOOL(cmrr.enable);
> +		PIPE_CONF_CHECK_I(vrr.dc_balance.vmin);
> +		PIPE_CONF_CHECK_I(vrr.dc_balance.vmax);
> +		PIPE_CONF_CHECK_I(vrr.dc_balance.guardband);
> +		PIPE_CONF_CHECK_I(vrr.dc_balance.slope);
> +		PIPE_CONF_CHECK_I(vrr.dc_balance.max_increase);
> +		PIPE_CONF_CHECK_I(vrr.dc_balance.max_decrease);
> +		PIPE_CONF_CHECK_I(vrr.dc_balance.vblank_target);
>  	}
>  
>  	if (!fastset || intel_vrr_always_use_vrr_tg(display)) {
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 30c7315fc25e..e5461900c15b 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1316,6 +1316,13 @@ struct intel_crtc_state {
>  		u8 pipeline_full;
>  		u16 flipline, vmin, vmax, guardband;
>  		u32 vsync_end, vsync_start;
> +		struct {
> +			bool enable;
> +			u16 vmin, vmax;
> +			u16 guardband, slope;
> +			u16 max_increase, max_decrease;
> +			u16 vblank_target;
> +		} dc_balance;
>  	} vrr;
>  
>  	/* Content Match Refresh Rate state */
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index d7bc35b07bab..4016da70ece2 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -10,6 +10,7 @@
>  #include "intel_display_regs.h"
>  #include "intel_display_types.h"
>  #include "intel_dp.h"
> +#include "intel_dmc_regs.h"

Please keep the includes sorted.

>  #include "intel_vrr.h"
>  #include "intel_vrr_regs.h"
>  
> @@ -699,6 +700,8 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
>  {
>  	struct intel_display *display = to_intel_display(crtc_state);
>  	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	enum pipe pipe = crtc->pipe;
>  	u32 trans_vrr_ctl, trans_vrr_vsync;
>  	bool vrr_enable;
>  
> @@ -761,6 +764,25 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
>  	else
>  		crtc_state->vrr.enable = vrr_enable;
>  
> +	if (HAS_VRR_DC_BALANCE(display)) {
> +		crtc_state->vrr.dc_balance.vmin =
> +			intel_de_read(display, PIPEDMC_DCB_VMIN(pipe)) ?
> +			intel_de_read(display, PIPEDMC_DCB_VMIN(pipe)) + 1 : 0;
> +		crtc_state->vrr.dc_balance.vmax =
> +			intel_de_read(display, PIPEDMC_DCB_VMAX(pipe)) ?
> +			intel_de_read(display, PIPEDMC_DCB_VMAX(pipe)) + 1 : 0;
> +		crtc_state->vrr.dc_balance.guardband =
> +			intel_de_read(display, PIPEDMC_DCB_GUARDBAND(pipe));
> +		crtc_state->vrr.dc_balance.max_increase =
> +			intel_de_read(display, PIPEDMC_DCB_MAX_INCREASE(pipe));
> +		crtc_state->vrr.dc_balance.max_decrease =
> +			intel_de_read(display, PIPEDMC_DCB_MAX_DECREASE(pipe));
> +		crtc_state->vrr.dc_balance.slope =
> +			intel_de_read(display, PIPEDMC_DCB_SLOPE(pipe));
> +		crtc_state->vrr.dc_balance.vblank_target =
> +			intel_de_read(display, PIPEDMC_DCB_VBLANK(pipe));
> +	}
> +
>  	/*
>  	 * #TODO: For Both VRR and CMRR the flag I915_MODE_FLAG_VRR is set for mode_flags.
>  	 * Since CMRR is currently disabled, set this flag for VRR for now.

-- 
Jani Nikula, Intel