[Intel-gfx] [PATCH v4 3/3] drm/i915/display: Refactor intel_commit_modeset_disables()

[Souza, Jose]

On Fri, 2019-12-06 at 14:22 -0800, Matt Roper wrote:
> On Thu, Dec 05, 2019 at 01:03:50PM -0800, José Roberto de Souza
> wrote:
> > Commit 9c722e17c1b9 ("drm/i915: Disable pipes in reverse order")
> > reverted the order that pipes gets disabled because of TGL
> > master/slave relationship between transcoders in MST mode.
> > 
> > But as stated in a comment in skl_commit_modeset_enables() the
> > enabling order is not always crescent, possibly causing previously
> > selected slave transcoder being enabled before master so another
> > approach will be needed to select a transcoder to master in MST
> > mode.
> > It will be similar to the approach taken in port sync.
> > 
> > But instead of implement something like
> > intel_trans_port_sync_modeset_disables() to MST lets simply it and
> > iterate over all pipes 2 times, the first one disabling any slave
> > and
> > then disabling everything else.
> > The MST bits will be added in another patch.
> > 
> > v2:
> > Not using crtc->active as it is deprecated
> > 
> > v3:
> > Removing is_trans_port_sync_mode() check, just check for
> > is_trans_port_sync_master() is enough
> > 
> > v4:
> > Adding and using is_trans_port_sync_slave(), otherwise non-port
> > sync
> > pipes will be disabled in the first loop, what is not wrong but is
> > not what patch description promises
> > 
> > Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> > Cc: Manasi Navare <manasi.d.navare at intel.com>
> > Cc: Matt Roper <matthew.d.roper at intel.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com> (v2)
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 88 +++++++---------
> > ----
> >  1 file changed, 32 insertions(+), 56 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 68575457d40e..821ba8053f9d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -561,6 +561,12 @@ is_trans_port_sync_master(const struct
> > intel_crtc_state *crtc_state)
> >  		crtc_state->sync_mode_slaves_mask);
> >  }
> >  
> > +static bool
> > +is_trans_port_sync_slave(const struct intel_crtc_state
> > *crtc_state)
> > +{
> > +	return crtc_state->master_transcoder != INVALID_TRANSCODER;
> > +}
> > +
> >  /*
> >   * Platform specific helpers to calculate the port PLL loopback-
> > (clock.m),
> >   * and post-divider (clock.p) values, pre- (clock.vco) and post-
> > divided fast
> > @@ -14393,77 +14399,47 @@ static void
> > intel_old_crtc_state_disables(struct intel_atomic_state *state,
> >  		dev_priv->display.initial_watermarks(state, crtc);
> >  }
> >  
> > -static void intel_trans_port_sync_modeset_disables(struct
> > intel_atomic_state *state,
> > -						   struct intel_crtc
> > *crtc,
> > -						   struct
> > intel_crtc_state *old_crtc_state,
> > -						   struct
> > intel_crtc_state *new_crtc_state)
> > -{
> > -	struct intel_crtc *slave_crtc =
> > intel_get_slave_crtc(new_crtc_state);
> > -	struct intel_crtc_state *new_slave_crtc_state =
> > -		intel_atomic_get_new_crtc_state(state, slave_crtc);
> > -	struct intel_crtc_state *old_slave_crtc_state =
> > -		intel_atomic_get_old_crtc_state(state, slave_crtc);
> > -
> > -	WARN_ON(!slave_crtc || !new_slave_crtc_state ||
> > -		!old_slave_crtc_state);
> > -
> > -	/* Disable Slave first */
> > -	intel_pre_plane_update(state, slave_crtc);
> > -	if (old_slave_crtc_state->hw.active)
> > -		intel_old_crtc_state_disables(state,
> > -					      old_slave_crtc_state,
> > -					      new_slave_crtc_state,
> > -					      slave_crtc);
> > -
> > -	/* Disable Master */
> > -	intel_pre_plane_update(state, crtc);
> > -	if (old_crtc_state->hw.active)
> > -		intel_old_crtc_state_disables(state,
> > -					      old_crtc_state,
> > -					      new_crtc_state,
> > -					      crtc);
> > -}
> > -
> >  static void intel_commit_modeset_disables(struct
> > intel_atomic_state *state)
> >  {
> >  	struct intel_crtc_state *new_crtc_state, *old_crtc_state;
> >  	struct intel_crtc *crtc;
> > +	u32 handled = 0;
> >  	int i;
> >  
> > -	/*
> > -	 * Disable CRTC/pipes in reverse order because some
> > features(MST in
> > -	 * TGL+) requires master and slave relationship between pipes,
> > so it
> > -	 * should always pick the lowest pipe as master as it will be
> > enabled
> > -	 * first and disable in the reverse order so the master will be
> > the
> > -	 * last one to be disabled.
> > -	 */
> > -	for_each_oldnew_intel_crtc_in_state_reverse(state, crtc,
> > old_crtc_state,
> > -						    new_crtc_state, i)
> > {
> > +	/* Only disable port sync slaves */
> > +	for_each_oldnew_intel_crtc_in_state(state, crtc,
> > old_crtc_state,
> > +					    new_crtc_state, i) {
> >  		if (!needs_modeset(new_crtc_state))
> >  			continue;
> >  
> > +		if (!old_crtc_state->hw.active)
> > +			continue;
> 
> Is it intentional that we skip the intel_pre_plane_update() in this
> case
> for the slaves, but not the masters?  Should this test be moved
> farther
> down below the pre_plane_update call?

If it was inative it is not a port sync slave, for the pipes going from
disabled to enabled in port sync slave mode the pre_plane_update() will
be executed in the second loop.

This is more of an optimization to not even check if is port sync slave
and in future if is MST slave.

I had a comment here but Ville asked to remove it. 
https://patchwork.freedesktop.org/patch/343736/?series=70462&rev=2

> 
> 
> Matt
> 
> > +
> >  		/* In case of Transcoder port Sync master slave CRTCs
> > can be
> >  		 * assigned in any order and we need to make sure that
> >  		 * slave CRTCs are disabled first and then master CRTC
> > since
> >  		 * Slave vblanks are masked till Master Vblanks.
> >  		 */
> > -		if (is_trans_port_sync_mode(old_crtc_state)) {
> > -			if (is_trans_port_sync_master(old_crtc_state))
> > -				intel_trans_port_sync_modeset_disables(
> > state,
> > -								       
> > crtc,
> > -								       
> > old_crtc_state,
> > -								       
> > new_crtc_state);
> > -			else
> > -				continue;
> > -		} else {
> > -			intel_pre_plane_update(state, crtc);
> > +		if (!is_trans_port_sync_slave(old_crtc_state))
> > +			continue;
> >  
> > -			if (old_crtc_state->hw.active)
> > -				intel_old_crtc_state_disables(state,
> > -							      old_crtc_
> > state,
> > -							      new_crtc_
> > state,
> > -							      crtc);
> > -		}
> > +		intel_pre_plane_update(state, crtc);
> > +		intel_old_crtc_state_disables(state, old_crtc_state,
> > +					      new_crtc_state, crtc);
> > +		handled |= BIT(crtc->pipe);
> > +	}
> > +
> > +	/* Disable everything else left on */
> > +	for_each_oldnew_intel_crtc_in_state(state, crtc,
> > old_crtc_state,
> > +					    new_crtc_state, i) {
> > +		if (!needs_modeset(new_crtc_state) ||
> > +		    (handled & BIT(crtc->pipe)))
> > +			continue;
> > +
> > +		intel_pre_plane_update(state, crtc);
> > +		if (old_crtc_state->hw.active)
> > +			intel_old_crtc_state_disables(state,
> > old_crtc_state,
> > +						      new_crtc_state,
> > crtc);
> >  	}
> >  }
> >  
> > -- 
> > 2.24.0
> >