[PATCH 1/2] drm/i915/display: After joiner compute pfit_dst

[Garg, Nemesa]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: Thursday, December 19, 2024 9:32 PM
> To: Garg, Nemesa <nemesa.garg at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; intel-xe at lists.freedesktop.org
> Subject: Re: [PATCH 1/2] drm/i915/display: After joiner compute pfit_dst
> 
> On Thu, Dec 12, 2024 at 08:03:28PM +0530, Nemesa Garg wrote:
> > In panel fitter/pipe scaler scenario the pch_pfit configuration
> > currently takes place before accounting for pipe_src width for joiner.
> > This causes issue when pch_pfit and joiner get enabled together.So
> > once pipe src is computed adjust the pfit_dst.
> > It can be done by computing per pipe output area first and then and
> > then find the intersection of above area with pfit_dst and then adjust
> > the coordinates.
> >
> > Signed-off-by: Nemesa Garg <nemesa.garg at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 41
> > ++++++++++++++++++++
> >  1 file changed, 41 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 21319f753a34..7be2ea11b8b0 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -2563,6 +2563,36 @@ static int intel_crtc_compute_pipe_src(struct
> intel_crtc_state *crtc_state)
> >  	return 0;
> >  }
> >
> > +/*
> > + * The x-coordinate for Primary should be calculated in such a way
> > + * that it remains consistent whether the pipes are joined or not.
> > + * This means we need to consider the full width of the display even
> > + * when the pipes are joined. The x-coordinate for secondaries is 0
> > + * because it starts at the leftmost point of its own display area,
> > + * ensuring that the framebuffer is centered within Pipe B’s portion
> > + * of the overall display.
> > + */
> > +static int intel_crtc_compute_pfit(struct intel_atomic_state *state,
> > +				   struct intel_crtc_state *crtc_state) {
> > +	struct drm_display_mode *mode = &crtc_state->hw.pipe_mode;
> 
> const struct drm_display_mode *pipe_mode = ...
> 
> > +	struct drm_rect area;
> > +
> > +	if (!crtc_state->pch_pfit.enabled)
> > +		return 0;
> > +
> > +	drm_rect_init(&area, 0, 0,
> 
> This needs a proper x offset to match the pipe's positon in the overall screen
> layout (can be determined similarly to intel_joiner_adjust_pipe_src(), except
> using crtc_hdisplay as the width instead of the pipe_src width).
> 
Thank you for the suggestion.  While implementing this code the problem was intel_crtc_compute_config() 
(intel_crtc_compute_pfit  is getting called from this) is getting called for primary pipe and not for secondary pipe so then I thought of finding a intersection point for primary pipe and then same thing can be translated for secondary pipe in copy_joiner_crtc_state_modeset(), but yes this will work for 2 pipes only, not for 4 pipes.

Regards,
Nemesa
> > +		      mode->crtc_hdisplay,
> > +		      mode->crtc_vdisplay);
> > +
> > +	if (!drm_rect_intersect(&crtc_state->pch_pfit.dst, &area))
> > +		return -EINVAL;
> > +
> > +	drm_rect_translate(&crtc_state->pch_pfit.dst, -area.x1, -area.y1);
> 
> And this needs to remove the same offset we added originally.
> 
> > +
> > +	return 0;
> > +}
> > +
> >  static int intel_crtc_compute_pipe_mode(struct intel_crtc_state
> > *crtc_state)  {
> >  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > @@ -2645,6 +2675,10 @@ static int intel_crtc_compute_config(struct
> intel_atomic_state *state,
> >  	if (ret)
> >  		return ret;
> >
> > +	ret = intel_crtc_compute_pfit(state, crtc_state);
> > +	if (ret)
> > +		return ret;
> > +
> >  	intel_crtc_compute_pixel_rate(crtc_state);
> >
> >  	if (crtc_state->has_pch_encoder)
> > @@ -4865,6 +4899,13 @@ copy_joiner_crtc_state_modeset(struct
> intel_atomic_state *state,
> >  		drm_dp_tunnel_ref_get(primary_crtc_state-
> >dp_tunnel_ref.tunnel,
> >  				      &secondary_crtc_state->dp_tunnel_ref);
> >
> > +	if (secondary_crtc_state->pch_pfit.enabled) {
> > +		struct drm_rect *dst = &secondary_crtc_state->pch_pfit.dst;
> > +		int y = dst->y1;
> > +
> > +		drm_rect_translate_to(dst, 0, y);
> > +	}
> > +
> >  	copy_joiner_crtc_state_nomodeset(state, secondary_crtc);
> >
> >  	secondary_crtc_state->uapi.mode_changed =
> > primary_crtc_state->uapi.mode_changed;
> > --
> > 2.25.1
> 
> --
> Ville Syrjälä
> Intel