RE: [PATCH 3/9] drm/i915: Introduce struct intel_vblank_evade_ctx

From: "Shankar, Uma" <uma.shankar@intel.com>
To: Ville Syrjala <ville.syrjala@linux.intel.com>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>
Subject: RE: [PATCH 3/9] drm/i915: Introduce struct intel_vblank_evade_ctx
Date: Wed, 20 Dec 2023 11:22:02 +0000	[thread overview]
Message-ID: <CY5PR11MB63444DD253EFE5F411C832C2F496A@CY5PR11MB6344.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20231213102519.13500-4-ville.syrjala@linux.intel.com>

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Ville
> Syrjala
> Sent: Wednesday, December 13, 2023 3:55 PM
> To: intel-gfx@lists.freedesktop.org
> Subject: [PATCH 3/9] drm/i915: Introduce struct intel_vblank_evade_ctx
> 
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Collect the information needed for vblank evasions into a structure that we can
> pass around more easily.
> 
> And let's rename intel_crtc_vblank_evade_scanlines() to just
> intel_vblank_evade_init() so that better describes the intended usage of
> initializing the context.

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

> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_crtc.c | 40 +++++++++++++----------
>  1 file changed, 22 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c
> b/drivers/gpu/drm/i915/display/intel_crtc.c
> index 4df8927bb062..93474fc9e502 100644
> --- a/drivers/gpu/drm/i915/display/intel_crtc.c
> +++ b/drivers/gpu/drm/i915/display/intel_crtc.c
> @@ -471,9 +471,13 @@ static int intel_mode_vblank_start(const struct
> drm_display_mode *mode)
>  	return vblank_start;
>  }
> 
> -static void intel_crtc_vblank_evade_scanlines(const struct intel_crtc_state
> *old_crtc_state,
> -					      const struct intel_crtc_state
> *new_crtc_state,
> -					      int *min, int *max, int *vblank_start)
> +struct intel_vblank_evade_ctx {
> +	int min, max, vblank_start;
> +};
> +
> +static void intel_vblank_evade_init(const struct intel_crtc_state *old_crtc_state,
> +				    const struct intel_crtc_state *new_crtc_state,
> +				    struct intel_vblank_evade_ctx *evade)
>  {
>  	struct intel_crtc *crtc = to_intel_crtc(new_crtc_state->uapi.crtc);
>  	const struct intel_crtc_state *crtc_state; @@ -498,17 +502,17 @@
> static void intel_crtc_vblank_evade_scanlines(const struct intel_crtc_state *old
>  			    new_crtc_state->update_m_n || new_crtc_state-
> >update_lrr);
> 
>  		if (intel_vrr_is_push_sent(crtc_state))
> -			*vblank_start = intel_vrr_vmin_vblank_start(crtc_state);
> +			evade->vblank_start =
> intel_vrr_vmin_vblank_start(crtc_state);
>  		else
> -			*vblank_start =
> intel_vrr_vmax_vblank_start(crtc_state);
> +			evade->vblank_start =
> intel_vrr_vmax_vblank_start(crtc_state);
>  	} else {
> -		*vblank_start = intel_mode_vblank_start(adjusted_mode);
> +		evade->vblank_start =
> intel_mode_vblank_start(adjusted_mode);
>  	}
> 
>  	/* FIXME needs to be calibrated sensibly */
> -	*min = *vblank_start - intel_usecs_to_scanlines(adjusted_mode,
> -
> 	VBLANK_EVASION_TIME_US);
> -	*max = *vblank_start - 1;
> +	evade->min = evade->vblank_start -
> intel_usecs_to_scanlines(adjusted_mode,
> +
> 	VBLANK_EVASION_TIME_US);
> +	evade->max = evade->vblank_start - 1;
> 
>  	/*
>  	 * M/N and TRANS_VTOTAL are double buffered on the transcoder's @@
> -519,7 +523,7 @@ static void intel_crtc_vblank_evade_scanlines(const struct
> intel_crtc_state *old
>  	 * hence we must kick off the commit before that.
>  	 */
>  	if (new_crtc_state->dsb || new_crtc_state->update_m_n ||
> new_crtc_state->update_lrr)
> -		*min -= adjusted_mode->crtc_vblank_start - adjusted_mode-
> >crtc_vdisplay;
> +		evade->min -= adjusted_mode->crtc_vblank_start -
> +adjusted_mode->crtc_vdisplay;
>  }
> 
>  /**
> @@ -544,10 +548,11 @@ void intel_pipe_update_start(struct intel_atomic_state
> *state,
>  	struct intel_crtc_state *new_crtc_state =
>  		intel_atomic_get_new_crtc_state(state, crtc);
>  	long timeout = msecs_to_jiffies_timeout(1);
> -	int scanline, min, max, vblank_start;
> +	int scanline;
>  	wait_queue_head_t *wq = drm_crtc_vblank_waitqueue(&crtc->base);
>  	bool need_vlv_dsi_wa = (IS_VALLEYVIEW(dev_priv) ||
> IS_CHERRYVIEW(dev_priv)) &&
>  		intel_crtc_has_type(new_crtc_state, INTEL_OUTPUT_DSI);
> +	struct intel_vblank_evade_ctx evade;
>  	DEFINE_WAIT(wait);
> 
>  	intel_psr_lock(new_crtc_state);
> @@ -565,9 +570,8 @@ void intel_pipe_update_start(struct intel_atomic_state
> *state,
>  	if (intel_crtc_needs_vblank_work(new_crtc_state))
>  		intel_crtc_vblank_work_init(new_crtc_state);
> 
> -	intel_crtc_vblank_evade_scanlines(old_crtc_state, new_crtc_state,
> -					  &min, &max, &vblank_start);
> -	if (min <= 0 || max <= 0)
> +	intel_vblank_evade_init(old_crtc_state, new_crtc_state, &evade);
> +	if (evade.min <= 0 || evade.max <= 0)
>  		goto irq_disable;
> 
>  	if (drm_WARN_ON(&dev_priv->drm, drm_crtc_vblank_get(&crtc-
> >base)))
> @@ -582,8 +586,8 @@ void intel_pipe_update_start(struct intel_atomic_state
> *state,
> 
>  	local_irq_disable();
> 
> -	crtc->debug.min_vbl = min;
> -	crtc->debug.max_vbl = max;
> +	crtc->debug.min_vbl = evade.min;
> +	crtc->debug.max_vbl = evade.max;
>  	trace_intel_pipe_update_start(crtc);
> 
>  	for (;;) {
> @@ -595,7 +599,7 @@ void intel_pipe_update_start(struct intel_atomic_state
> *state,
>  		prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
> 
>  		scanline = intel_get_crtc_scanline(crtc);
> -		if (scanline < min || scanline > max)
> +		if (scanline < evade.min || scanline > evade.max)
>  			break;
> 
>  		if (!timeout) {
> @@ -629,7 +633,7 @@ void intel_pipe_update_start(struct intel_atomic_state
> *state,
>  	 *
>  	 * FIXME figure out if BXT+ DSI suffers from this as well
>  	 */
> -	while (need_vlv_dsi_wa && scanline == vblank_start)
> +	while (need_vlv_dsi_wa && scanline == evade.vblank_start)
>  		scanline = intel_get_crtc_scanline(crtc);
> 
>  	drm_crtc_vblank_put(&crtc->base);
> --
> 2.41.0