Re: [PATCH] drm/i915/psr: Implment WA to help reach PC10

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On Mon, 2024-09-02 at 10:14 +0000, Kandpal, Suraj wrote:
> 
> 
> > -----Original Message-----
> > From: Hogander, Jouni <jouni.hogander@xxxxxxxxx>
> > Sent: Monday, September 2, 2024 3:32 PM
> > To: Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>; intel-
> > gfx@xxxxxxxxxxxxxxxxxxxxx
> > Cc: Shankar, Uma <uma.shankar@xxxxxxxxx>
> > Subject: Re: [PATCH] drm/i915/psr: Implment WA to help reach PC10
> > 
> > On Mon, 2024-09-02 at 12:37 +0300, Hogander, Jouni wrote:
> > > On Mon, 2024-09-02 at 10:32 +0530, Suraj Kandpal 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.
> > > > 
> > > > --v2
> > > > -Switch condition and do an early return [Jani] -Do some checks
> > > > in
> > > > compute_config [Jani] -Do not use register reads as a method of
> > > > checking states for DPKGC or delayed vblank [Jani] -Use another
> > > > way
> > > > to see is vblank interrupts are disabled or not [Jani]
> > > > 
> > > > --v3
> > > > -Use has_psr to check if psr can be enabled or not for
> > > > dc5_entry
> > > > cond [Uma] -Move the dc5 entry computation to
> > > > psr_compute_config
> > > > [Jouni] -No need to change sequence of enabled and activate, so
> > > > dont
> > > > make hsw_psr1_activate return anything [Jouni] -Use has_psr to
> > > > stop
> > > > psr1 activation [Jouni] -Use lineage no. in WA -Add the display
> > > > ver
> > > > restrictions for WA
> > > > 
> > > > WA: 22019444797
> > > > Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> > > > ---
> > > >  .../drm/i915/display/intel_display_types.h    |  2 +
> > > >  drivers/gpu/drm/i915/display/intel_psr.c      | 96
> > > > ++++++++++++++++++-
> > > >  2 files changed, 97 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > index 868ff8976ed9..5395c1ecde7f 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > @@ -1717,6 +1717,8 @@ struct intel_psr {
> > > >         bool sink_support;
> > > >         bool source_support;
> > > >         bool enabled;
> > > > +       bool is_dpkgc_configured;
> > > > +       bool is_dc5_entry_possible;
> > > >         bool paused;
> > > >         enum pipe pipe;
> > > >         enum transcoder transcoder;
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > > > b/drivers/gpu/drm/i915/display/intel_psr.c
> > > > index 257526362b39..1faec76eac32 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > > > @@ -870,6 +870,69 @@ static u8 psr_compute_idle_frames(struct
> > > > intel_dp *intel_dp)
> > > >         return idle_frames;
> > > >  }
> > > > 
> > > > +static bool intel_psr_check_delayed_vblank_limit(struct
> > > > intel_crtc_state *crtc_state)
> > > 
> > > You could add some context here in the name. This is somehow
> > > telling
> > > it's some generic delayed vblank limit while it is actually limit
> > > for
> > > this workaround.
> > > 
> > > > +{
> > > > +       struct drm_display_mode *adjusted_mode = &crtc_state-
> > > > > hw.adjusted_mode;
> > > > +
> > > > +       return (adjusted_mode->crtc_vblank_start -
> > > > adjusted_mode-
> > > > > crtc_vdisplay) >= 6;
> > > > +}
> > > > +
> > > > +/*
> > > > + * PKG_C_LATENCY is configured only when DISPLAY_VER >= 20 and
> > > > + * VRR is not enabled
> > > > + */
> > > > +static bool intel_psr_is_dpkgc_configured(struct
> > > > drm_i915_private
> > > > *i915)
> > > > +{
> > > > +       struct intel_crtc *intel_crtc;
> > > > +
> > > > +       if (DISPLAY_VER(i915) < 20)
> > > > +               return false;
> > > > +
> > > > +       for_each_intel_crtc(&i915->drm, intel_crtc) {
> > > > +               struct intel_crtc_state *crtc_state;
> > > > +
> > > > +               if (!intel_crtc->active)
> > > > +                       continue;
> > > > +
> > > > +               crtc_state = intel_crtc->config;
> > > > +
> > > > +               if (crtc_state->vrr.enable)
> > > > +                       return false;
> > > > +       }
> > > > +
> > > > +       return true;
> > > > +}
> > > > +
> > > > +/*
> > > > + * DC5 entry is only possible if vblank interrupt is disabled
> > > > + * and either psr1, psr2, edp 1.5 pr alpm is enabled on all
> > > > + * enabled encoders.
> > > > + */
> > > > +static bool
> > > > +intel_psr_is_dc5_entry_possible(struct drm_i915_private *i915,
> > > > +                               struct intel_crtc_state
> > > > *crtc_state)
> > > > +{
> > > > +       struct intel_crtc *intel_crtc;
> > > > +
> > > > +       if (!(crtc_state->has_psr || crtc_state-
> > > > >has_sel_update))
> > > > +               return false;
> > > 
> > > Currently this is not returning for DP2.1 PR. This would better
> > > match
> > > with comment above:
> > > 
> > > if (!crtc_state->has_psr || !intel_dp_is_edp(intel_dp))
> > >     return false;
> > > 
> > > Still "_all_ enabled encoders" is not handled...
> > > 
> > > BR,
> > > 
> > > Jouni Högander
> > > 
> > > > +
> > > > +       for_each_intel_crtc(&i915->drm, intel_crtc) {
> > > > +               struct drm_crtc *crtc = &intel_crtc->base;
> > > > +               struct drm_vblank_crtc *vblank;
> > > > +
> > > > +               if (!intel_crtc->active)
> > > > +                       continue;
> > > > +
> > > > +               vblank = drm_crtc_vblank_crtc(crtc);
> > > > +
> > > > +               if (vblank->enabled)
> > > > +                       return false;
> > > > +       }
> > > > +
> > > > +       return true;
> > > > +}
> > > > +
> > > >  static void hsw_activate_psr1(struct intel_dp *intel_dp)
> > > >  {
> > > >         struct drm_i915_private *dev_priv =
> > > > dp_to_i915(intel_dp); @@
> > > > -980,7 +1043,11 @@ 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_22019444797 */
> > > > +       if (DISPLAY_VER(dev_priv) != 20 ||
> > 
> > I think this is wrong. It will not configure idle frames for
> > display version
> > other than 20.
> 
> Wouldn’t this configure idle frames for all versions except 20 
> And if it is 20 then if dpkgc is configured and dc5 entry is possible
> Only then configure idle frames

Yes. My bad. sorry for that. This should be ok for display version !=
20. Another thing here. WA description is:

"When PKG_C_LATENCY is configured (not all 1s), enable PSR2 deep sleep
(PSR2_CTL Idle Frames != 0) only when DC5 can be entered."

How about case where PKG_C_LATENCY is not configured? Do we need to
care about it?

BR,

Jouni Högander

> 
> Regards,
> Suraj Kandpal
> > 
> > BR,
> > 
> > Jouni Högander
> > 
> > > > +           (intel_dp->psr.is_dpkgc_configured &&
> > > > +            intel_dp->psr.is_dc5_entry_possible))
> > > > +               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; @@ -1595,6 +1662,32
> > > > @@
> > > > _panel_replay_compute_config(struct intel_dp *intel_dp,
> > > >         return true;
> > > >  }
> > > > 
> > > > +static void wa_22019444797(struct intel_dp *intel_dp,
> > > > +                          struct intel_crtc_state *crtc_state)
> > > > {
> > > > +       struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > > +
> > > > +       if (DISPLAY_VER(i915) != 20)
> > > > +               return;
> > > > +
> > > > +       intel_dp->psr.is_dpkgc_configured =
> > > > +               intel_psr_is_dpkgc_configured(i915);
> > > > +       intel_dp->psr.is_dc5_entry_possible =
> > > > +               intel_psr_is_dc5_entry_possible(i915,
> > > > crtc_state);
> > > > +
> > > > +       /* PSR2 not handled here. Wa not needed for Panel
> > > > Replay */
> > > > +       if (crtc_state->has_sel_update || crtc_state-
> > > > > has_panel_replay)
> > > > +               return;
> > > > +
> > > > +       if (intel_dp->psr.is_dpkgc_configured &&
> > > > +           (intel_psr_check_delayed_vblank_limit(crtc_state)
> > > > ||
> > > > +            intel_dp->psr.is_dc5_entry_possible)) {
> > > > +               drm_dbg_kms(&i915->drm,
> > > > +                           "PSR1 not enabled as it doesn't
> > > > meet
> > > > requirements of WA: 22019444797\n");
> > > > +               crtc_state->has_psr = false;
> > > > +       }
> > > > +}
> > > > +
> > > >  void intel_psr_compute_config(struct intel_dp *intel_dp,
> > > >                               struct intel_crtc_state
> > > > *crtc_state,
> > > >                               struct drm_connector_state
> > > > *conn_state)
> > > > @@ -1641,6 +1734,7 @@ void intel_psr_compute_config(struct
> > > > intel_dp
> > > > *intel_dp,
> > > >                 return;
> > > > 
> > > >         crtc_state->has_sel_update =
> > > > intel_sel_update_config_valid(intel_dp, crtc_state);
> > > > +       wa_22019444797(intel_dp, crtc_state);
> > > >  }
> > > > 
> > > >  void intel_psr_get_config(struct intel_encoder *encoder,
> > > 
> 





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