[Intel-gfx] [PATCH 6/7] drm/i915/display/tgl: Fix the order of the step to turn transcoder clock off

[Souza, Jose]

On Thu, 2019-11-28 at 20:40 +0200, Ville Syrjälä wrote:
> On Fri, Nov 22, 2019 at 04:54:58PM -0800, José Roberto de Souza
> wrote:
> > For TGL the step to turn off the transcoder clock was moved to
> > after
> > the complete shutdown of DDI. Only the MST slave transcoders should
> > disable the clock before that.
> > 
> > BSpec: 49190
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_ddi.c    |  9 ++++++++-
> >  drivers/gpu/drm/i915/display/intel_dp_mst.c | 15 ++++++++++++---
> >  2 files changed, 20 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> > b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index cfcaa7c81575..aa0249333175 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -3813,7 +3813,7 @@ static void intel_ddi_post_disable_dp(struct
> > intel_encoder *encoder,
> >  	 */
> >  	intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
> >  
> > -	if (!is_mst)
> > +	if (INTEL_GEN(dev_priv) < 12 && !is_mst)
> >  		intel_ddi_disable_pipe_clock(old_crtc_state);
> >  
> >  	intel_disable_ddi_buf(encoder, old_crtc_state);
> > @@ -3826,6 +3826,13 @@ static void intel_ddi_post_disable_dp(struct
> > intel_encoder *encoder,
> >  		intel_display_power_put_unchecked(dev_priv,
> >  						  dig_port-
> > >ddi_io_power_domain);
> >  
> > +	/*
> > +	 * From TGL BSpec "If single stream or multi-stream master
> > transcoder:
> > +	 * Configure Transcoder Clock select to direct no clock to the
> > +	 * transcoder"
> > +	 */
> 
> Not really convinced these comments add anything the code isn't
> already saying.

We have added similar comments in tgl_ddi_pre_enable_dp(), it helps
tracks the code with BSpec steps.

> 
> > +	if (INTEL_GEN(dev_priv) >= 12)
> > +		intel_ddi_disable_pipe_clock(old_crtc_state);
> 
> That's much later than the bspec sequence suggests.

Oh, thanks.
Yeah it should right after intel_disable_ddi_buf()

> 
> >  	intel_ddi_clk_disable(encoder);
> >  	tgl_clear_psr2_transcoder_exitline(old_crtc_state);
> >  }
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > index 94549848653a..53afe3e179f7 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > @@ -369,8 +369,19 @@ static void intel_mst_post_disable_dp(struct
> > intel_encoder *encoder,
> >  	struct intel_dp *intel_dp = &intel_dig_port->dp;
> >  	struct intel_connector *connector =
> >  		to_intel_connector(old_conn_state->connector);
> > +	struct drm_i915_private *dev_priv = to_i915(connector-
> > >base.dev);
> >  
> > -	intel_ddi_disable_pipe_clock(old_crtc_state);
> > +	intel_dp->active_mst_links--;
> > +
> > +	/*
> > +	 * From TGL BSpec "If multi-stream slave transcoder: Configure
> > +	 * Transcoder Clock Select to direct no clock to the
> > transcoder"
> > +	 *
> > +	 * From older GENs BSpec "Configure Transcoder Clock Select to
> > direct
> > +	 * no clock to the transcoder"
> > +	 */
> > +	if (INTEL_GEN(dev_priv) < 12 || intel_dp->active_mst_links)
> 
> Maybe we should add 'last_mst_stream' to mirror the
> 'first_mst_stream'
> in the enable code?

Sounds good

> 
> > +		intel_ddi_disable_pipe_clock(old_crtc_state);
> >  
> >  	/* this can fail */
> >  	drm_dp_check_act_status(&intel_dp->mst_mgr);
> > @@ -386,8 +397,6 @@ static void intel_mst_post_disable_dp(struct
> > intel_encoder *encoder,
> >  	drm_dp_send_power_updown_phy(&intel_dp->mst_mgr, connector-
> > >port,
> >  				     false);
> >  
> > -	intel_dp->active_mst_links--;
> > -
> >  	intel_mst->connector = NULL;
> >  	if (intel_dp->active_mst_links == 0) {
> >  		intel_dig_port->base.post_disable(&intel_dig_port-
> > >base,
> > -- 
> > 2.24.0
> > 
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