Re: [PATCH v11 08/18] drm/i915/vrr: Add function to check if DC Balance Possible

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

On 12/23/2025 4:15 PM, Mitul Golani wrote:
> Add function to check if DC Balance possibile on
> requested PIPE and also validate along with DISPLAY_VER
> check.

s/possibile/possible

Perhaps it can be rephrased as:

Add a function that checks if DC Balance enabling is possible on the
requested PIPE. Apart from the DISPLAY_VER check, account for current
firmware limitations, which only allow DC Balance on PIPE A and PIPE B.

With the above changes:

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

>
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_vrr.c | 19 +++++++++++++++++--
>   1 file changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 952e3c31bacc..dbfe56e8973d 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -351,13 +351,28 @@ int intel_vrr_compute_vmax(struct intel_connector *connector,
>   	return vmax;
>   }
>   
> +static bool intel_vrr_dc_balance_possible(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	enum pipe pipe = crtc->pipe;
> +
> +	/*
> +	 * FIXME: Currently Firmware supports DC Balancing on PIPE A
> +	 * and PIPE B. Account those limitation while computing DC
> +	 * Balance parameters.
> +	 */
> +	return (HAS_VRR_DC_BALANCE(display) &&
> +		((pipe == PIPE_A) || (pipe == PIPE_B)));
> +}
> +
>   static void
>   intel_vrr_dc_balance_compute_config(struct intel_crtc_state *crtc_state)
>   {
>   	int guardband_usec, adjustment_usec;
>   	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
>   
> -	if (!HAS_VRR_DC_BALANCE(display) || !crtc_state->vrr.enable)
> +	if (!intel_vrr_dc_balance_possible(crtc_state) || !crtc_state->vrr.enable)
>   		return;
>   
>   	crtc_state->vrr.dc_balance.vmax = crtc_state->vrr.vmax;
> @@ -839,7 +854,7 @@ void intel_vrr_get_dc_balance_config(struct intel_crtc_state *crtc_state)
>   	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>   	enum pipe pipe = crtc->pipe;
>   
> -	if (!HAS_VRR_DC_BALANCE(display))
> +	if (!intel_vrr_dc_balance_possible(crtc_state))
>   		return;
>   
>   	reg_val = intel_de_read(display, PIPEDMC_DCB_VMIN(pipe));