Re: [PATCH v1] drm/i915/display: Add command line param for DC balance

["Borah, Chaitanya Kumar" <chaitanya.kumar.borah@intel.com>]

On 8/28/2026 2:20 PM, Mitul Golani wrote:
> Add a new module parameter 'enable_dc_balance' to allow enabling or
> disabling the VRR DC balance feature at runtime. The DC balance
> computation in intel_vrr_dc_balance_compute_config() now honours this
> parameter, so the feature can be toggled without recompiling.
> 
> Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_display_params.c | 3 +++
>   drivers/gpu/drm/i915/display/intel_display_params.h | 1 +
>   drivers/gpu/drm/i915/display/intel_vrr.c            | 4 +++-
>   3 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c
> index 2aed110c5b09..ed3aa84c5d43 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_params.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_params.c
> @@ -120,6 +120,9 @@ intel_display_param_named_unsafe(enable_psr, int, 0400,
>   	"(0=disabled, 1=enable up to PSR1, 2=enable up to PSR2) "
>   	"Default: -1 (use per-chip default)");
>   
> +intel_display_param_named_unsafe(enable_dc_balance, int, 0400,
> +	"Enable DC Balance (0=disabled, 1=enable). Default: 1 (use per-chip default)");
> +
>   intel_display_param_named_unsafe(enable_panel_replay, int, 0400,
>   	"Enable Panel Replay (0=disabled, 1=enabled). Default: -1 (use per-chip default)");
>   
> diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h
> index b95ecf728daa..8c28c27e2c46 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_params.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_params.h
> @@ -46,6 +46,7 @@ struct drm_printer;
>   	param(bool, enable_dp_mst, true, 0600) \
>   	param(int, enable_fbc, -1, 0600) \
>   	param(int, enable_psr, -1, 0600) \
> +	param(int, enable_dc_balance, false, 0600) \

You mean true?

>   	param(int, enable_panel_replay, -1, 0600) \
>   	param(bool, psr_safest_params, false, 0400) \
>   	param(bool, enable_psr2_sel_fetch, true, 0400) \
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index e36db1174440..1698c54e258b 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -439,10 +439,12 @@ static bool intel_vrr_dc_balance_possible(const struct intel_crtc_state *crtc_st
>   static void
>   intel_vrr_dc_balance_compute_config(struct intel_crtc_state *crtc_state)
>   {
> +	struct intel_display *display = to_intel_display(crtc_state);
>   	int guardband_usec, adjustment_usec;
>   	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
>   
> -	if (!intel_vrr_dc_balance_possible(crtc_state) || !crtc_state->vrr.enable)
> +	if (!intel_vrr_dc_balance_possible(crtc_state) ||
> +	    !crtc_state->vrr.enable || !display->params.enable_dc_balance)
>   		return;
>   
>   	crtc_state->vrr.dc_balance.vmax = crtc_state->vrr.vmax;