RE: [PATCH 06/12] drm/i915/alpm: Add function to compute max link-wake latency

[Golani, Mitulkumar Ajitkumar]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-boun...@lists.freedesktop.org> On Behalf Of Ankit
> Nautiyal
> Sent: 18 August 2025 13:01
> To: intel-gfx@lists.freedesktop.org; intel...@lists.freedesktop.org
> Cc: ville.syrj...@linux.intel.com; Nautiyal, Ankit K 
> <ankit.k.nauti...@intel.com>
> Subject: [PATCH 06/12] drm/i915/alpm: Add function to compute max link-
> wake latency
> 
> Introduce a helper to compute the max link wake latency when using
> Auxless/Aux wake mechanism for PSR/Panel Replay/LOBF features.
> 
> This will be used to compute the minimum guardband so that the link wake
> latencies are accounted and these features work smoothly for higher refresh 
> rate
> panels.
> 
> Bspec: 70151, 71477
> Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_alpm.c | 15 +++++++++++++++
> drivers/gpu/drm/i915/display/intel_alpm.h |  2 ++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c
> b/drivers/gpu/drm/i915/display/intel_alpm.c
> index dfdde8e4eabe..42b4a0ceb53b 100644
> --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> @@ -628,3 +628,18 @@ bool intel_alpm_get_error(struct intel_dp *intel_dp)
> 
>       return false;
>  }
> +
> +int intel_alpm_compute_max_link_wake_latency(struct intel_crtc_state
> *crtc_state,
> +                                          bool assume_all_enabled)
> +{
> +     int psr2_vblank_time = 0;
> +     int auxless_wake_time = 0;
> +
> +     if (assume_all_enabled || crtc_state->has_sel_update)
> +             psr2_vblank_time =  io_buffer_wake_time(crtc_state);
> +
> +     if (assume_all_enabled || crtc_state->has_panel_replay)
> +             auxless_wake_time =
> +_lnl_compute_aux_less_wake_time(crtc_state->port_clock);
> +
> +     return max(psr2_vblank_time, auxless_wake_time); }
> diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h
> b/drivers/gpu/drm/i915/display/intel_alpm.h
> index a861c20b5d79..8f1db54eecf5 100644
> --- a/drivers/gpu/drm/i915/display/intel_alpm.h
> +++ b/drivers/gpu/drm/i915/display/intel_alpm.h
> @@ -38,4 +38,6 @@ bool intel_alpm_is_alpm_aux_less(struct intel_dp
> *intel_dp,
>                                const struct intel_crtc_state *crtc_state);  
> void
> intel_alpm_disable(struct intel_dp *intel_dp);  bool 
> intel_alpm_get_error(struct
> intel_dp *intel_dp);
> +int intel_alpm_compute_max_link_wake_latency(struct intel_crtc_state
> *crtc_state,
> +                                          bool assume_all_enabled);

Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.gol...@intel.com>

>  #endif
> --
> 2.45.2