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

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> -----Original Message-----
> From: Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>
> Sent: Monday, September 9, 2024 12:02 PM
> To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: Shankar, Uma <uma.shankar@xxxxxxxxx>; Hogander, Jouni
> <jouni.hogander@xxxxxxxxx>; Deak, Imre <imre.deak@xxxxxxxxx>; Kandpal, Suraj
> <suraj.kandpal@xxxxxxxxx>
> Subject: [PATCH] drm/i915/psr: Implment WA to help reach PC10

Not: Typo in implement

> 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
> 
> --v4
> -use more appropriate name for check_vblank_limit() [Jouni] -Cover the case for
> idle frames when dpkgc is not configured [Jouni] -Check psr only for edp [Jouni]
> 
> --v5
> -move psr1 handling to plane update [Jouni] -add todo for cases when vblank is
> enabled when psr enabled [Jouni] -use intel_display instead of drm_i915_private
> 
> --v6
> -check target_dc_state [Jouni]
> -fix condition in pre/post plane update [Jouni]
> 
> WA: 22019444797
> Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> ---
>  .../drm/i915/display/intel_display_types.h    |   3 +
>  drivers/gpu/drm/i915/display/intel_psr.c      | 112 +++++++++++++++++-
>  2 files changed, 114 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 733de5edcfdb..59c81f0a3abd 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1577,6 +1577,9 @@ struct intel_psr {
>  #define I915_PSR_DEBUG_PANEL_REPLAY_DISABLE	0x40
> 
>  	u32 debug;
> +	bool is_dpkgc_configured;
> +	bool is_dc5_entry_possible;
> +	bool is_wa_delayed_vblank_limit;
>  	bool sink_support;
>  	bool source_support;
>  	bool enabled;
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> b/drivers/gpu/drm/i915/display/intel_psr.c
> index b30fa067ce6e..e50b476494a0 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -26,6 +26,7 @@
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_damage_helper.h>
>  #include <drm/drm_debugfs.h>
> +#include <drm/drm_vblank.h>
> 
>  #include "i915_drv.h"
>  #include "i915_reg.h"
> @@ -874,6 +875,78 @@ static u8 psr_compute_idle_frames(struct intel_dp
> *intel_dp)
>  	return idle_frames;
>  }
> 
> +static bool
> +intel_psr_check_wa_delayed_vblank(const struct drm_display_mode
> +*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 intel_display *display,
> +					  struct intel_atomic_state *state) {
> +	struct intel_crtc *intel_crtc;
> +	struct intel_crtc_state *crtc_state;
> +	int i;
> +
> +	if (DISPLAY_VER(display) < 20)
> +		return false;
> +
> +	for_each_new_intel_crtc_in_state(state, intel_crtc, crtc_state, i) {
> +		if (!intel_crtc->active)
> +			continue;
> +
> +		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 intel_display *display,
> +				struct intel_atomic_state *state)
> +{
> +	struct intel_crtc *intel_crtc;
> +	struct intel_crtc_state *crtc_state;
> +	int i;
> +
> +	if ((display->power.domains.target_dc_state &
> +	     DC_STATE_EN_UPTO_DC5_DC6_MASK) == 0)
> +		return false;
> +
> +	for_each_new_intel_crtc_in_state(state, intel_crtc, crtc_state, i) {
> +		struct drm_crtc *crtc = &intel_crtc->base;
> +		struct drm_vblank_crtc *vblank;
> +		struct intel_encoder *encoder;
> +
> +		if (!intel_crtc->active)
> +			continue;
> +
> +		vblank = drm_crtc_vblank_crtc(crtc);
> +
> +		if (vblank->enabled)
> +			return false;
> +
> +		if (crtc_state->has_psr)
> +			return false;

It should be !has_psr 

> +
> +		for_each_encoder_on_crtc(display->drm, crtc, encoder)
> +			if (encoder->type != INTEL_OUTPUT_EDP)
> +				return false;
> +	}
> +
> +	return true;
> +}
> +
>  static void hsw_activate_psr1(struct intel_dp *intel_dp)  {
>  	struct intel_display *display = to_intel_display(intel_dp); @@ -986,7
> +1059,15 @@ 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
> +	 * TODO: Disable idle frames when vblank gets enabled while
> +	 * PSR2 is enabled
> +	 */
> +	if (DISPLAY_VER(dev_priv) != 20 ||
> +	    !intel_dp->psr.is_dpkgc_configured ||

Why ! for dpkgc, Here this can be enabled if dpkgc_configured right ?

> +	    intel_dp->psr.is_dc5_entry_possible)
> +		val |=
> EDP_PSR2_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
> 
>  	if (DISPLAY_VER(display) < 14 && !IS_ALDERLAKE_P(dev_priv))
>  		val |= EDP_SU_TRACK_ENABLE;
> @@ -2667,10 +2748,20 @@ void intel_psr_pre_plane_update(struct
> intel_atomic_state *state,
>  	const struct intel_crtc_state *new_crtc_state =
>  		intel_atomic_get_new_crtc_state(state, crtc);
>  	struct intel_encoder *encoder;
> +	bool dpkgc_configured = false, dc5_entry_possible = false;
> +	bool wa_delayed_vblank_limit = false;
> 
>  	if (!HAS_PSR(display))
>  		return;
> 
> +	if (DISPLAY_VER(display) == 20) {
> +		dpkgc_configured = intel_psr_is_dpkgc_configured(display,
> state);
> +		dc5_entry_possible =
> +			intel_psr_is_dc5_entry_possible(display, state);
> +		wa_delayed_vblank_limit =
> +			intel_psr_check_wa_delayed_vblank(&new_crtc_state-
> >hw.adjusted_mode);
> +	}
> +
>  	for_each_intel_encoder_mask_with_psr(state->base.dev, encoder,
>  					     old_crtc_state->uapi.encoder_mask)
> {
>  		struct intel_dp *intel_dp = enc_to_intel_dp(encoder); @@ -
> 2679,6 +2770,12 @@ void intel_psr_pre_plane_update(struct intel_atomic_state
> *state,
> 
>  		mutex_lock(&psr->lock);
> 
> +		if (DISPLAY_VER(i915) == 20) {
> +			psr->is_dpkgc_configured = dpkgc_configured;
> +			psr->is_dc5_entry_possible = dc5_entry_possible;
> +			psr->is_wa_delayed_vblank_limit =
> wa_delayed_vblank_limit;

We can drop the variables and directly assign this to psr->... and use it subsequently.
Also it would be good to have this done in compute and than just use it here.

> +		}
> +
>  		/*
>  		 * Reasons to disable:
>  		 * - PSR disabled in new state
> @@ -2686,6 +2783,7 @@ void intel_psr_pre_plane_update(struct
> intel_atomic_state *state,
>  		 * - Changing between PSR versions
>  		 * - Region Early Transport changing
>  		 * - Display WA #1136: skl, bxt
> +		 * - Display WA_22019444797
>  		 */
>  		needs_to_disable |=
> intel_crtc_needs_modeset(new_crtc_state);
>  		needs_to_disable |= !new_crtc_state->has_psr; @@ -2695,6
> +2793,10 @@ void intel_psr_pre_plane_update(struct intel_atomic_state *state,
>  			psr->su_region_et_enabled;
>  		needs_to_disable |= DISPLAY_VER(i915) < 11 &&
>  			new_crtc_state->wm_level_disabled;
> +		/* TODO: Disable PSR1 when vblank gets enabled while PSR1 is
> enabled */
> +		needs_to_disable |= DISPLAY_VER(display) == 20 &&
> dpkgc_configured &&
> +			(wa_delayed_vblank_limit || dc5_entry_possible) &&
> +			!new_crtc_state->has_sel_update &&
> +!new_crtc_state->has_panel_replay;

Good to move this to a small helper function which can be extended if required as well.
Also seems used in post_plane as well.

@Hogander, Jouni Can you also ack if this handling for PSR is ok.

>  		if (psr->enabled && needs_to_disable)
>  			intel_psr_disable_locked(intel_dp);
> @@ -2735,6 +2837,14 @@ void intel_psr_post_plane_update(struct
> intel_atomic_state *state,
>  		keep_disabled |= DISPLAY_VER(display) < 11 &&
>  			crtc_state->wm_level_disabled;
> 
> +		/*
> +		 * Wa_22019444797
> +		 * TODO: Disable PSR1 when vblank gets enabled while PSR1 is
> enabled
> +		 */
> +		keep_disabled |= DISPLAY_VER(display) == 20 && psr-
> >is_dpkgc_configured &&
> +			(psr->is_wa_delayed_vblank_limit || psr-
> >is_dc5_entry_possible) &&
> +			!crtc_state->has_sel_update && !crtc_state-
> >has_panel_replay;
> +
>  		if (!psr->enabled && !keep_disabled)
>  			intel_psr_enable_locked(intel_dp, crtc_state);
>  		else if (psr->enabled && !crtc_state->wm_level_disabled)
> --
> 2.43.2





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