[Intel-gfx] [PATCH 2/2] drm/i915: Remove duplicate DDI enabling logic from MST path

[Ville Syrjälä]

On Tue, Feb 28, 2017 at 03:59:52PM +0200, Imre Deak wrote:
> On Tue, Feb 28, 2017 at 09:21:13AM +0200, Ander Conselvan de Oliveira wrote:
> > The logic to enable a DDI in intel_mst_pre_enable_dp() is essentially
> > the same as in intel_ddi_pre_enable_dp(). So reuse the latter function
> > by calling the post_disable hook on the intel_dig_port instead of
>                  ^pre_enable
> > duplicating that code.
> > 
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c    |  2 ++
> >  drivers/gpu/drm/i915/intel_dp_mst.c | 23 +++--------------------
> >  2 files changed, 5 insertions(+), 20 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index e9013f1..71aaddf 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -1695,6 +1695,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
> >  	enum port port = intel_ddi_get_encoder_port(encoder);
> >  	struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base);
> >  
> > +	WARN_ON(link_mst && port == PORT_A);
> > +
> 
> So IIUC, this wasn't used before for MST and so link_mst was always
> false.

The MST code explicitly passes 'true' here.

> Also link_mst=true implies type == INTEL_OUTPUT_DP, as this will
> be called for the primary encoder. After the change crtc->config will be
> used instead of the (new) pipe_config, but this is fine since the two
> are the same in the enable hooks.

Nope. AFAICS this should explode totally since encoder->crtc for the
primary will be NULL. I guess Maarten didn't yet nuke all crtc->config
usage from the ddi code (or he did but the patches didn't get reviewed).

> Looks ok to me:
> 
> Reviewed-by: Imre Deak <imre.deak at intel.com>
> 
> >  	intel_dp_set_link_params(intel_dp, link_rate, lane_count,
> >  				 link_mst);
> >  	if (encoder->type == INTEL_OUTPUT_EDP)
> > diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> > index a8334e1..094cbdc 100644
> > --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> > @@ -159,26 +159,9 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder,
> >  
> >  	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
> >  
> > -	if (intel_dp->active_mst_links == 0) {
> > -		intel_ddi_clk_select(&intel_dig_port->base,
> > -				     pipe_config->shared_dpll);
> > -
> > -		intel_display_power_get(dev_priv,
> > -					intel_dig_port->ddi_io_power_domain);
> > -
> > -		intel_prepare_dp_ddi_buffers(&intel_dig_port->base);
> > -		intel_dp_set_link_params(intel_dp,
> > -					 pipe_config->port_clock,
> > -					 pipe_config->lane_count,
> > -					 true);
> > -
> > -		intel_ddi_init_dp_buf_reg(&intel_dig_port->base);
> > -
> > -		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
> > -
> > -		intel_dp_start_link_train(intel_dp);
> > -		intel_dp_stop_link_train(intel_dp);
> > -	}
> > +	if (intel_dp->active_mst_links == 0)
> > +		intel_dig_port->base.pre_enable(&intel_dig_port->base,
> > +						pipe_config, NULL);
> >  
> >  	ret = drm_dp_mst_allocate_vcpi(&intel_dp->mst_mgr,
> >  				       connector->port,
> > -- 
> > 2.9.3
> > 
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-- 
Ville Syrjälä
Intel OTC