[PATCH v4 04/21] drm/i915/dsb: Garbage collect the MMIO DEwake stuff

[Shankar, Uma]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> Syrjala
> Sent: Monday, June 9, 2025 7:40 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: intel-xe at lists.freedesktop.org
> Subject: [PATCH v4 04/21] drm/i915/dsb: Garbage collect the MMIO DEwake stuff
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Since the introduction of DSB chaining we no longer need the DEwake tricks in
> intel_dsb_commit().
> 
> I also need to relocate the DSB_PMCTRL* writes out of
> intel_dsb_finish() (due to the flip queue DMC vs. DSB register corruption issues),
> and it'll be a bit more straightforward if I don't have to worry about the non-chained
> DSB path anymore.

Looks Good to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c |  4 +-
>  drivers/gpu/drm/i915/display/intel_dsb.c     | 45 ++++----------------
>  drivers/gpu/drm/i915/display/intel_dsb.h     |  3 +-
>  3 files changed, 11 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> b/drivers/gpu/drm/i915/display/intel_display.c
> index b0c7c46ffbe2..6ec786198f43 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -6748,13 +6748,13 @@ static void intel_update_crtc(struct
> intel_atomic_state *state,
>  	if (new_crtc_state->use_dsb) {
>  		intel_crtc_prepare_vblank_event(new_crtc_state, &crtc-
> >dsb_event);
> 
> -		intel_dsb_commit(new_crtc_state->dsb_commit, false);
> +		intel_dsb_commit(new_crtc_state->dsb_commit);
>  	} else {
>  		/* Perform vblank evasion around commit operation */
>  		intel_pipe_update_start(state, crtc);
> 
>  		if (new_crtc_state->dsb_commit)
> -			intel_dsb_commit(new_crtc_state->dsb_commit, false);
> +			intel_dsb_commit(new_crtc_state->dsb_commit);
> 
>  		commit_pipe_pre_planes(state, crtc);
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c
> b/drivers/gpu/drm/i915/display/intel_dsb.c
> index c8011f5e4076..200555a9e94b 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -826,8 +826,13 @@ void intel_dsb_wait_vblank_delay(struct
> intel_atomic_state *state,
>  	intel_dsb_wait_usec(dsb, usecs);
>  }
> 
> -static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
> -			      int hw_dewake_scanline)
> +/**
> + * intel_dsb_commit() - Trigger workload execution of DSB.
> + * @dsb: DSB context
> + *
> + * This function is used to do actual write to hardware using DSB.
> + */
> +void intel_dsb_commit(struct intel_dsb *dsb)
>  {
>  	struct intel_crtc *crtc = dsb->crtc;
>  	struct intel_display *display = to_intel_display(crtc->base.dev); @@ -
> 843,7 +848,7 @@ static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
>  	}
> 
>  	intel_de_write_fw(display, DSB_CTRL(pipe, dsb->id),
> -			  ctrl | DSB_ENABLE);
> +			  DSB_ENABLE);
> 
>  	intel_de_write_fw(display, DSB_CHICKEN(pipe, dsb->id),
>  			  dsb->chicken);
> @@ -855,44 +860,10 @@ static void _intel_dsb_commit(struct intel_dsb *dsb,
> u32 ctrl,
>  	intel_de_write_fw(display, DSB_HEAD(pipe, dsb->id),
>  			  intel_dsb_head(dsb));
> 
> -	if (hw_dewake_scanline >= 0) {
> -		int diff, position;
> -
> -		intel_de_write_fw(display, DSB_PMCTRL(pipe, dsb->id),
> -				  DSB_ENABLE_DEWAKE |
> -
> DSB_SCANLINE_FOR_DEWAKE(hw_dewake_scanline));
> -
> -		/*
> -		 * Force DEwake immediately if we're already past
> -		 * or close to racing past the target scanline.
> -		 */
> -		position = intel_de_read_fw(display, PIPEDSL(display, pipe)) &
> PIPEDSL_LINE_MASK;
> -
> -		diff = hw_dewake_scanline - position;
> -		intel_de_write_fw(display, DSB_PMCTRL_2(pipe, dsb->id),
> -				  (diff >= 0 && diff < 5 ? DSB_FORCE_DEWAKE :
> 0) |
> -				  DSB_BLOCK_DEWAKE_EXTENSION);
> -	}
> -
>  	intel_de_write_fw(display, DSB_TAIL(pipe, dsb->id),
>  			  intel_dsb_tail(dsb));
>  }
> 
> -/**
> - * intel_dsb_commit() - Trigger workload execution of DSB.
> - * @dsb: DSB context
> - * @wait_for_vblank: wait for vblank before executing
> - *
> - * This function is used to do actual write to hardware using DSB.
> - */
> -void intel_dsb_commit(struct intel_dsb *dsb,
> -		      bool wait_for_vblank)
> -{
> -	_intel_dsb_commit(dsb,
> -			  wait_for_vblank ? DSB_WAIT_FOR_VBLANK : 0,
> -			  wait_for_vblank ? dsb->hw_dewake_scanline : -1);
> -}
> -
>  void intel_dsb_wait(struct intel_dsb *dsb)  {
>  	struct intel_crtc *crtc = dsb->crtc;
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h
> b/drivers/gpu/drm/i915/display/intel_dsb.h
> index 6bcfb03f3415..c8f4499916eb 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.h
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.h
> @@ -68,8 +68,7 @@ void intel_dsb_chain(struct intel_atomic_state *state,
>  		     struct intel_dsb *chained_dsb,
>  		     bool wait_for_vblank);
> 
> -void intel_dsb_commit(struct intel_dsb *dsb,
> -		      bool wait_for_vblank);
> +void intel_dsb_commit(struct intel_dsb *dsb);
>  void intel_dsb_wait(struct intel_dsb *dsb);
> 
>  void intel_dsb_irq_handler(struct intel_display *display,
> --
> 2.49.0