On Thu, 06 Jun 2024, Suraj Kandpal <[email protected]> wrote:
> To reach PC10 when PKG_C_LATENCY is configure we must do the following
> things
> 1) Enter PSR1 only when delayed_vblank < 6 lines and DC5 can be entered
> 2) Allow PSR2 deep sleep when DC5 can be entered
> 3) DC5 can be entered when all transocoder have either PSR1, PSR2 or
> eDP 1.5 PR ALPM enabled and VBI is disabled and flips and pushes are
> not happening.
>
> WA: 16023497226
> Signed-off-by: Suraj Kandpal <[email protected]>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 75 +++++++++++++++++++++++-
>  1 file changed, 73 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c 
> b/drivers/gpu/drm/i915/display/intel_psr.c
> index 6fc88f6c6b26..b22745c019df 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -811,12 +811,81 @@ static u8 psr_compute_idle_frames(struct intel_dp 
> *intel_dp)
>       return idle_frames;
>  }
>  
> +static bool intel_psr_check_delayed_vblank_limit(struct drm_i915_private 
> *i915,
> +                                              enum transcoder cpu_transcoder)
> +{
> +     return intel_de_read(i915, TRANS_SET_CONTEXT_LATENCY(cpu_transcoder)) 
> >= 6;

Please don't use the hardware to preserve the state for you. It will get
really complicated to maintain.

> +}
> +
> +static bool intel_psr_is_dpkgc_configured(struct drm_i915_private *i915)
> +{
> +     return intel_de_read(i915, LNL_PKG_C_LATENCY) == U32_MAX;

Ditto.

> +}
> +
> +static bool intel_psr_is_dc5_entry_possible(struct drm_i915_private *i915)
> +{
> +     struct intel_crtc *intel_crtc;
> +     bool ret = true;
> +
> +     for_each_intel_crtc(&i915->drm, intel_crtc) {
> +             struct intel_encoder *encoder;
> +             struct drm_crtc *crtc = &intel_crtc->base;
> +             enum pipe pipe = intel_crtc->pipe;
> +
> +             if (!crtc->active)
> +                     continue;
> +
> +             if (!(i915->display.irq.de_irq_mask[pipe] & GEN8_PIPE_VBLANK))

You have no business looking directly at that. It's for display irq code
*only*.

> +                     ret = false;
> +
> +             for_each_encoder_on_crtc(&i915->drm, crtc, encoder) {
> +                     struct intel_dp *intel_dp = enc_to_intel_dp(_encoder);
> +                     struct intel_psr *psr = &intel_dp->psr;
> +
> +                     if (!psr->enabled)
> +                             ret = false;
> +             }
> +     }
> +
> +     return ret;
> +}
> +
> +static bool wa_16023497226_check(struct intel_dp *intel_dp, bool psr1)
> +{
> +     struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +     enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
> +
> +     if (DISPLAY_VER(i915) != 20)
> +             return true;
> +
> +     if (is_dpkg_c_configured(i915)) {
> +             if (psr1 &&
> +                 (intel_psr_check_delayed_vblank_limit(i915, cpu_transcoder) 
> ||
> +                  intel_psr_is_dc5_entry_possible(i915)))
> +                     return true;
> +             else if (!psr1 && is_dc5_entry_possible(i915))
> +                     return true;
> +             else
> +                     return false;
> +     }
> +
> +     return true;
> +}
> +
>  static bool hsw_activate_psr1(struct intel_dp *intel_dp)
>  {
>       struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>       enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
>       u32 max_sleep_time = 0x1f;
> -     u32 val = EDP_PSR_ENABLE;
> +     u32 val = 0;
> +
> +     /* WA: 16023497226*/
> +     if (wa_16023497226_check(intel_dp, true)) {
> +             val = EDP_PSR_ENABLE;
> +     } else {
> +             drm_dbg_kms(&dev_priv->drm, "PSR1 was not activated\n");

Please add reason.

> +             return false;
> +     }

Switch the condition around and use early return.

>  
>       val |= EDP_PSR_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
>  
> @@ -910,7 +979,9 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
>       u32 val = EDP_PSR2_ENABLE;
>       u32 psr_val = 0;
>  
> -     val |= EDP_PSR2_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
> +     /* WA: 16023497226*/
> +     if (wa_16023497226_check(intel_dp, false))
> +             val |= EDP_PSR2_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
>  
>       if (DISPLAY_VER(dev_priv) < 14 && !IS_ALDERLAKE_P(dev_priv))
>               val |= EDP_SU_TRACK_ENABLE;

-- 
Jani Nikula, Intel

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