[PATCH v7 5/8] drm/i915/lobf: Update lobf if any change in dependent parameters

[Manna, Animesh]

> -----Original Message-----
> From: Hogander, Jouni <jouni.hogander at intel.com>
> Sent: Tuesday, April 8, 2025 1:25 PM
> To: intel-xe at lists.freedesktop.org; Manna, Animesh
> <animesh.manna at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Nikula, Jani <jani.nikula at intel.com>; B, Jeevan <jeevan.b at intel.com>
> Subject: Re: [PATCH v7 5/8] drm/i915/lobf: Update lobf if any change in
> dependent parameters
> 
> On Thu, 2025-04-03 at 14:58 +0530, Animesh Manna wrote:
> > For every commit the dependent condition for LOBF is checked and
> > accordingly update has_lobf flag which will be used to update the
> > ALPM_CTL register during commit.
> >
> > v1: Initial version.
> > v2: Avoid reading h/w register without has_lobf check. [Jani]
> > v3: Update LOBF in post plane update instead of separate function.
> > [Jouni]
> > v4:
> > - Add lobf disable print. [Jouni]
> > - Simplify condition check for enabling/disabling lobf. [Jouni]
> >
> > Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_alpm.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c
> > b/drivers/gpu/drm/i915/display/intel_alpm.c
> > index aae2c322baa7..7ab29c5fef38 100644
> > --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> > +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> > @@ -360,6 +360,8 @@ static void lnl_alpm_configure(struct intel_dp
> > *intel_dp,
> >  	if (crtc_state->has_lobf) {
> >  		alpm_ctl |= ALPM_CTL_LOBF_ENABLE;
> >  		drm_dbg_kms(display->drm, "Link off between frames
> > (LOBF) enabled\n");
> > +	} else {
> > +		drm_dbg_kms(display->drm, "Link off between frames
> > (LOBF) disabled\n");
> >  	}
> >
> >  	alpm_ctl |= ALPM_CTL_ALPM_ENTRY_CHECK(intel_dp-
> > >alpm_parameters.check_entry_lines);
> > @@ -380,9 +382,12 @@ void intel_alpm_post_plane_update(struct
> > intel_atomic_state *state,
> >  	struct intel_display *display = to_intel_display(state);
> >  	const struct intel_crtc_state *crtc_state =
> >  		intel_atomic_get_new_crtc_state(state, crtc);
> > +	const struct intel_crtc_state *old_crtc_state =
> > +		intel_atomic_get_old_crtc_state(state, crtc);
> >  	struct intel_encoder *encoder;
> >
> > -	if (!crtc_state->has_lobf && !crtc_state->has_psr)
> > +	if (!(crtc_state->has_lobf != old_crtc_state->has_lobf) &&
> 
> I usually support artistic freedom... I think here you should really do
> 
> crtc_state->has_lobf == old_crtc_state->has_lobf

Ok.

Regards,
Animesh

> 
> BR,
> 
> Jouni Högander
> 
> 
> > +	    !crtc_state->has_psr)
> >  		return;
> >
> >  	for_each_intel_encoder_mask(display->drm, encoder,