Periodic AS SDP (skip frames) drives a Panel Replay panel down toward its minimum refresh rate. It is a new, panel- and platform-sensitive behaviour, so keep it opt-in rather than enabling it unconditionally.
Add a display module parameter, periodic_assdp_enable, shared by both the i915 and xe drivers via the intel_display_params infrastructure. It defaults to false (feature disabled); set it to true to enable periodic AS SDP. Gate the feature at its single choke point, intel_pr_as_sdp_skip_frames(): returning a zero skip count when the parameter is off makes both the PR_ALPM_CTL programming (intel_alpm_configure_pr_as_sdp()) and the DC3co force-disable predicate (intel_alpm_pr_as_sdp_skip_frames_enabled()) a no-op, so AS SDP continues to be sent on every frame as before. Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Uma Shankar <[email protected]> --- drivers/gpu/drm/i915/display/intel_alpm.c | 5 +++++ drivers/gpu/drm/i915/display/intel_display_params.c | 6 ++++++ drivers/gpu/drm/i915/display/intel_display_params.h | 1 + 3 files changed, 12 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c index c784e77f610b..537cad13f0b4 100644 --- a/drivers/gpu/drm/i915/display/intel_alpm.c +++ b/drivers/gpu/drm/i915/display/intel_alpm.c @@ -392,11 +392,16 @@ static u32 get_pr_alpm_as_sdp_transmission_time(const struct intel_crtc_state *c */ static u32 intel_pr_as_sdp_skip_frames(struct intel_dp *intel_dp) { + struct intel_display *display = to_intel_display(intel_dp); const struct drm_display_info *info = &intel_dp->attached_connector->base.display_info; int max_vrefresh = info->monitor_range.max_vfreq; int min_vrefresh = info->monitor_range.min_vfreq; + /* Off by default; gated by the periodic_assdp_enable module parameter. */ + if (!display->params.periodic_assdp_enable) + return 0; + if (min_vrefresh <= 0 || max_vrefresh <= min_vrefresh) return 0; diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c index 2aed110c5b09..a845d29610cf 100644 --- a/drivers/gpu/drm/i915/display/intel_display_params.c +++ b/drivers/gpu/drm/i915/display/intel_display_params.c @@ -139,6 +139,12 @@ intel_display_param_named_unsafe(enable_dmc_wl, int, 0400, "(-1=use per-chip default, 0=disabled, 1=enabled, 2=match any register, 3=always locked) " "Default: -1"); +intel_display_param_named_unsafe(periodic_assdp_enable, bool, 0600, + "Enable periodic Adaptive-Sync SDP (AS SDP skip frames) for Panel Replay " + "to drive the panel down to its minimum refresh rate " + "(0=disabled, 1=enabled) " + "Default: 0"); + __maybe_unused static void _param_print_bool(struct drm_printer *p, const char *driver_name, const char *name, bool val) diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h index b95ecf728daa..4d912aab4811 100644 --- a/drivers/gpu/drm/i915/display/intel_display_params.h +++ b/drivers/gpu/drm/i915/display/intel_display_params.h @@ -50,6 +50,7 @@ struct drm_printer; param(bool, psr_safest_params, false, 0400) \ param(bool, enable_psr2_sel_fetch, true, 0400) \ param(int, enable_dmc_wl, -1, 0400) \ + param(bool, periodic_assdp_enable, false, 0600) \ #define MEMBER(T, member, ...) T member; struct intel_display_params { -- 2.50.1
