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

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Feb 28, 2017 at 04:47:51PM +0200, Ville Syrjälä wrote:
> On Tue, Feb 28, 2017 at 04:33:46PM +0200, Imre Deak wrote:
> > On Tue, Feb 28, 2017 at 04:09:31PM +0200, Ville Syrjälä wrote:
> > > 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@linux.intel.com>
> > > > > Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@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.
> > 
> > Yes, after the change.
> 
> It was 'true' before. After the change it'll be 'intel_crtc_has_type(MST)'

Ahem. So I thought we were talking about intel_dp_set_link_params(), but
really this was about intel_ddi_pre_enable_dp(). So yes, you're correct
that intel_ddi_pre_enable_dp() was not actually used for MST.

> 
> > I was just wondering why this wasn't used for MST
> > before.
> > 
> > > 
> > > > 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).
> > 
> > Err, right. So this would need first changing to use crtc->config to
> > pipe_config in intel_ddi_pre_enable.
> 
> + review all the code that gets called from there to make sure no more
> users are lurking somewhere deeper.
> 
> > 
> > --Imre
> > 
> > > 
> > > > Looks ok to me:
> > > > 
> > > > Reviewed-by: Imre Deak <imre.deak@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
> 
> -- 
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
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-- 
Ville Syrjälä
Intel OTC
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