Compute DC Balance parameters and tunable params based on experiments. --v2: - Document tunable params. (Ankit)
--v3: - Add line spaces to compute config. (Ankit) - Remove redundancy checks. --v4: - Separate out conpute config to separate function. - As all the valuse are being computed in scanlines, and slope is still in usec, convert and store it to scanlines. --v5: - Update and add comments for slope calculation. (Ankit) - Update early return conditions for dc balance compute. (Ankit) --v6: - Early return condition simplified for dc balance compute config. (Ankit) - Make use of pipe restrictions to this patch. (Ankit) --v7: - Separate out PIPE_A and PIPE_B restrictions to other patch.(Ankit) Signed-off-by: Mitul Golani <[email protected]> Reviewed-by: Uma Shankar <[email protected]> --- drivers/gpu/drm/i915/display/intel_vrr.c | 45 ++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c index 427ef1741051..952e3c31bacc 100644 --- a/drivers/gpu/drm/i915/display/intel_vrr.c +++ b/drivers/gpu/drm/i915/display/intel_vrr.c @@ -6,6 +6,7 @@ #include <drm/drm_print.h> +#include "intel_crtc.h" #include "intel_de.h" #include "intel_display_regs.h" #include "intel_display_types.h" @@ -20,6 +21,14 @@ #define FIXED_POINT_PRECISION 100 #define CMRR_PRECISION_TOLERANCE 10 +/* + * Tunable parameters for DC Balance correction. + * These are captured based on experimentations. + */ +#define DCB_CORRECTION_SENSITIVITY 30 +#define DCB_CORRECTION_AGGRESSIVENESS 1000 /* ms × 100; 10 ms */ +#define DCB_BLANK_TARGET 50 + bool intel_vrr_is_capable(struct intel_connector *connector) { struct intel_display *display = to_intel_display(connector); @@ -342,6 +351,40 @@ int intel_vrr_compute_vmax(struct intel_connector *connector, return vmax; } +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) + return; + + crtc_state->vrr.dc_balance.vmax = crtc_state->vrr.vmax; + crtc_state->vrr.dc_balance.vmin = crtc_state->vrr.vmin; + crtc_state->vrr.dc_balance.max_increase = + crtc_state->vrr.vmax - crtc_state->vrr.vmin; + crtc_state->vrr.dc_balance.max_decrease = + crtc_state->vrr.vmax - crtc_state->vrr.vmin; + crtc_state->vrr.dc_balance.guardband = + DIV_ROUND_UP(crtc_state->vrr.dc_balance.vmax * + DCB_CORRECTION_SENSITIVITY, 100); + guardband_usec = + intel_scanlines_to_usecs(adjusted_mode, + crtc_state->vrr.dc_balance.guardband); + /* + * The correction_aggressiveness/100 is the number of milliseconds to + * adjust by when the balance is at twice the guardband. + * guardband_slope = correction_aggressiveness / (guardband * 100) + */ + adjustment_usec = DCB_CORRECTION_AGGRESSIVENESS * 10; + crtc_state->vrr.dc_balance.slope = + DIV_ROUND_UP(adjustment_usec, guardband_usec); + crtc_state->vrr.dc_balance.vblank_target = + DIV_ROUND_UP((crtc_state->vrr.vmax - crtc_state->vrr.vmin) * + DCB_BLANK_TARGET, 100); +} + void intel_vrr_compute_config(struct intel_crtc_state *crtc_state, struct drm_connector_state *conn_state) @@ -399,6 +442,8 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state, (crtc_state->hw.adjusted_mode.crtc_vtotal - crtc_state->hw.adjusted_mode.crtc_vsync_end); } + + intel_vrr_dc_balance_compute_config(crtc_state); } static int -- 2.48.1
