> -----Original Message-----
> From: Hogander, Jouni <jouni.hogander@xxxxxxxxx>
> Sent: Friday, May 3, 2024 12:49 PM
> To: Manna, Animesh <animesh.manna@xxxxxxxxx>; intel-
> gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx; Murthy, Arun R
> <arun.r.murthy@xxxxxxxxx>; Nikula, Jani <jani.nikula@xxxxxxxxx>
> Subject: Re: [PATCH v3 4/6] drm/i915/alpm: Add compute config for lobf
>
> On Thu, 2024-04-25 at 00:08 +0530, Animesh Manna wrote:
> > Link Off Between Active Frames, is a new feature for eDP
> > that allows the panel to go to lower power state after
> > transmission of data. This is a feature on top of ALPM, AS SDP.
> > Add compute config during atomic-check phase.
> >
> > v1: RFC version.
> > v2: Add separate flag for auxless-alpm. [Jani]
> > v3:
> > - intel_dp->lobf_supported replaced with crtc_state->has_lobf.
> > [Jouni]
> > - Add DISPLAY_VER() check. [Jouni]
> > - Modify function name of get_aux_less_status. [Jani]
> >
> > Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_alpm.c | 48
> > +++++++++++++++++++
> > drivers/gpu/drm/i915/display/intel_alpm.h | 5 ++
> > .../drm/i915/display/intel_display_types.h | 4 ++
> > drivers/gpu/drm/i915/display/intel_dp.c | 4 ++
> > 4 files changed, 61 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c
> > b/drivers/gpu/drm/i915/display/intel_alpm.c
> > index 13bac3e8c8fa..3bb69ed16aab 100644
> > --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> > +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> > @@ -11,6 +11,16 @@
> > #include "intel_dp_aux.h"
> > #include "intel_psr_regs.h"
> >
> > +bool intel_alpm_get_aux_less_status(struct intel_dp *intel_dp)
> > +{
> > + u8 alpm_caps = 0;
> > +
> > + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_RECEIVER_ALPM_CAP,
> > + &alpm_caps) != 1)
> > + return false;
> > + return alpm_caps & DP_ALPM_AUX_LESS_CAP;
> > +}
> > +
> > /*
> > * See Bspec: 71632 for the table
> > *
> > @@ -242,6 +252,44 @@ bool intel_alpm_compute_params(struct intel_dp
> > *intel_dp,
> > return true;
> > }
> >
> > +void intel_alpm_compute_lobf_config(struct intel_dp *intel_dp,
> > + struct intel_crtc_state
> > *crtc_state,
> > + struct drm_connector_state
> > *conn_state)
> > +{
> > + struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > + struct drm_display_mode *adjusted_mode = &crtc_state-
> > >hw.adjusted_mode;
> > + int waketime_in_lines, first_sdp_position;
> > + int context_latency, guardband;
> > +
> > + crtc_state->has_lobf = false;
>
> Drop this line. I think crtc_state is reset before doing this
> compute_config
Sure.
>
> > +
> > + if (!intel_dp_is_edp(intel_dp))
> > + return;
> > +
> > + if (DISPLAY_VER(i915) < 20)
> > + return;
> > +
> > + if (!intel_dp_as_sdp_supported(intel_dp))
> > + return;
> > +
> > + if (crtc_state->has_psr)
> > + return;
> > +
> > + if (intel_alpm_compute_params(intel_dp, crtc_state)) {
>
> I think it is easier to read and helps avoiding big if blocks if you:
>
> if (!intel_alpm_compute_params(intel_dp, crtc_state())
> return;
Ok.
>
> This actually brings up another thing: do we want to spread intel_psr.c
> pollution by continue using these boolean return values? I would prefer
> changing intel_alpm_compute_params return value to "normal" int
> approach and return 0 on success. This would mean one more patch
> changing it.
Ok.
>
> > + context_latency = adjusted_mode->crtc_vblank_start -
> > adjusted_mode->crtc_vdisplay;
> > + guardband = adjusted_mode->crtc_vtotal -
> > + adjusted_mode->crtc_vdisplay -
> > context_latency;
> > + first_sdp_position = adjusted_mode->crtc_vtotal -
> > adjusted_mode->crtc_vsync_start;
> > + if (intel_dp->alpm_parameters.auxless_alpm_supported)
> > + waketime_in_lines = intel_dp-
> > >alpm_parameters.io_wake_lines;
> > + else
> > + waketime_in_lines = intel_dp-
> > >alpm_parameters.fast_wake_lines;
> > +
> > + if ((context_latency + guardband) >
> > (first_sdp_position + waketime_in_lines))
> > + crtc_state->has_lobf = true;
>
> crtc_state->has_lobf = (context_latency + guardband) >
> (first_sdp_position + waketime_in_lines);
Ok.
>
> > + }
> > +}
> > +
> > static void lnl_alpm_configure(struct intel_dp *intel_dp)
> > {
> > struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h
> > b/drivers/gpu/drm/i915/display/intel_alpm.h
> > index c45d078e5a6b..b9602b71d28f 100644
> > --- a/drivers/gpu/drm/i915/display/intel_alpm.h
> > +++ b/drivers/gpu/drm/i915/display/intel_alpm.h
> > @@ -10,9 +10,14 @@
> >
> > struct intel_dp;
> > struct intel_crtc_state;
> > +struct drm_connector_state;
> >
> > +bool intel_alpm_get_aux_less_status(struct intel_dp *intel_dp);
> > bool intel_alpm_compute_params(struct intel_dp *intel_dp,
> > struct intel_crtc_state *crtc_state);
> > +void intel_alpm_compute_lobf_config(struct intel_dp *intel_dp,
> > + struct intel_crtc_state
> > *crtc_state,
> > + struct drm_connector_state
> > *conn_state);
> > void intel_alpm_configure(struct intel_dp *intel_dp);
> >
> > #endif
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index d94f50c6dc6c..5a0ffd5aa48b 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1405,6 +1405,9 @@ struct intel_crtc_state {
> >
> > /* for loading single buffered registers during vblank */
> > struct drm_vblank_work vblank_work;
> > +
> > + /* LOBF flag */
> > + bool has_lobf;
> > };
> >
> > enum intel_pipe_crc_source {
> > @@ -1835,6 +1838,7 @@ struct intel_dp {
> > u8 fast_wake_lines;
> >
> > /* LNL and beyond */
> > + bool auxless_alpm_supported;
> > u8 check_entry_lines;
> > u8 silence_period_sym_clocks;
> > u8 lfps_half_cycle_num_of_syms;
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > b/drivers/gpu/drm/i915/display/intel_dp.c
> > index e05e25cd4a94..563739c6014c 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -48,6 +48,7 @@
> > #include "i915_drv.h"
> > #include "i915_irq.h"
> > #include "i915_reg.h"
> > +#include "intel_alpm.h"
> > #include "intel_atomic.h"
> > #include "intel_audio.h"
> > #include "intel_backlight.h"
> > @@ -2997,6 +2998,7 @@ intel_dp_compute_config(struct intel_encoder
> > *encoder,
> > intel_vrr_compute_config(pipe_config, conn_state);
> > intel_dp_compute_as_sdp(intel_dp, pipe_config);
> > intel_psr_compute_config(intel_dp, pipe_config, conn_state);
> > + intel_alpm_compute_lobf_config(intel_dp, pipe_config,
> > conn_state);
> > intel_dp_drrs_compute_config(connector, pipe_config,
> > link_bpp_x16);
> > intel_dp_compute_vsc_sdp(intel_dp, pipe_config, conn_state);
> > intel_dp_compute_hdr_metadata_infoframe_sdp(intel_dp,
> > pipe_config, conn_state);
> > @@ -6612,6 +6614,8 @@ static bool intel_edp_init_connector(struct
> > intel_dp *intel_dp,
> >
> > intel_pps_init_late(intel_dp);
> >
> > + intel_dp->alpm_parameters.auxless_alpm_supported =
> > intel_alpm_get_aux_less_status(intel_dp);
>
> How about aux_wake ?
I felt auxless_alpm_supported will give both aux-less and aux-wake info, if it is true then aux-less otherwise aux-wake. Do you see any issue here?
Regards,
Animesh
>
> > +
> > return true;
> >
> > out_vdd_off:
