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kernel
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linux
drm/i915/alpm: Calculate silence period
Calculate silence period instead of hardcoding it in switch case.
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Link: https://lore.kernel.org/r/20250829053929.3585636-2-jouni.hogander@intel.com
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drivers/gpu/drm/i915/display/intel_alpm.c
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drivers/gpu/drm/i915/display/intel_alpm.c
···
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#include "intel_psr.h"
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#include "intel_psr_regs.h"
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#define SILENCE_PERIOD_MIN_TIME 80
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#define SILENCE_PERIOD_MAX_TIME 180
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#define SILENCE_PERIOD_TIME (SILENCE_PERIOD_MIN_TIME + \
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(SILENCE_PERIOD_MAX_TIME - \
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SILENCE_PERIOD_MIN_TIME) / 2)
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+
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bool intel_alpm_aux_wake_supported(struct intel_dp *intel_dp)
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{
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return intel_dp->alpm_dpcd & DP_ALPM_CAP;
···
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mutex_init(&intel_dp->alpm_parameters.lock);
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}
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static int get_silence_period_symbols(const struct intel_crtc_state *crtc_state)
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{
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return SILENCE_PERIOD_TIME * intel_dp_link_symbol_clock(crtc_state->port_clock) /
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1000 / 1000;
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}
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+
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/*
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* See Bspec: 71632 for the table
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-
*
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* Silence_period = tSilence,Min + ((tSilence,Max - tSilence,Min) / 2)
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*
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* Half cycle duration:
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*
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* FLOOR( LFPS Period in Symbol clocks /
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* (2 * PORT_ALPM_LFPS_CTL[ LFPS Cycle Count ]) )
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*/
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static bool _lnl_get_silence_period_and_lfps_half_cycle(int link_rate,
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int *silence_period,
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int *lfps_half_cycle)
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static bool _lnl_get_lfps_half_cycle(int link_rate, int *lfps_half_cycle)
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{
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switch (link_rate) {
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case 162000:
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*silence_period = 20;
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*lfps_half_cycle = 5;
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break;
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case 216000:
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*silence_period = 27;
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*lfps_half_cycle = 7;
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break;
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case 243000:
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*silence_period = 31;
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*lfps_half_cycle = 8;
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break;
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case 270000:
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*silence_period = 34;
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*lfps_half_cycle = 9;
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break;
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case 324000:
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*silence_period = 41;
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*lfps_half_cycle = 11;
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break;
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case 432000:
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*silence_period = 56;
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*lfps_half_cycle = 15;
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break;
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case 540000:
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*silence_period = 69;
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*lfps_half_cycle = 12;
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break;
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case 648000:
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*silence_period = 84;
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*lfps_half_cycle = 15;
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break;
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case 675000:
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*silence_period = 87;
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*lfps_half_cycle = 15;
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break;
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case 810000:
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*silence_period = 104;
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*lfps_half_cycle = 19;
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break;
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default:
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*silence_period = *lfps_half_cycle = -1;
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*lfps_half_cycle = -1;
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return false;
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}
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return true;
···
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_lnl_compute_aux_less_wake_time(crtc_state->port_clock);
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aux_less_wake_lines = intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode,
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aux_less_wake_time);
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if (!_lnl_get_silence_period_and_lfps_half_cycle(crtc_state->port_clock,
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&silence_period,
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&lfps_half_cycle))
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silence_period = get_silence_period_symbols(crtc_state);
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if (!_lnl_get_lfps_half_cycle(crtc_state->port_clock,
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&lfps_half_cycle))
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return false;
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if (aux_less_wake_lines > ALPM_CTL_AUX_LESS_WAKE_TIME_MASK ||