Re: [PATCH 2/7] drm/i915/dp: move link_bw and rate_select debugging where used

[Manasi Navare <manasi.d.navare@intel.com>]

On Thu, Apr 05, 2018 at 10:22:38AM -0700, Rodrigo Vivi wrote:
> On Thu, Apr 05, 2018 at 05:39:00PM +0300, Jani Nikula wrote:
> > The debug prints make more sense where the results are actually used,
> > and this cleans up extra clutter from the already overcrowded
> > intel_dp_compute_config().
> > 
> > Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c               | 9 ++-------
> >  drivers/gpu/drm/i915/intel_dp_link_training.c | 5 +++++
> >  2 files changed, 7 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index 5f4b30faf6a2..81cf363e71af 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1706,7 +1706,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> >  	int bpp, mode_rate;
> >  	int link_avail, link_clock;
> >  	int common_len;
> > -	uint8_t link_bw, rate_select;
> >  	bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc,
> >  					   DP_DPCD_QUIRK_LIMITED_M_N);
> >  
> > @@ -1852,12 +1851,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> >  	pipe_config->pipe_bpp = bpp;
> >  	pipe_config->port_clock = intel_dp->common_rates[clock];
> >  
> > -	intel_dp_compute_rate(intel_dp, pipe_config->port_clock,
> > -			      &link_bw, &rate_select);
> 
> the commit message state more about the debug message itself,
> but by removing this call here it seems that you change
> the behavior of eDP. So I couldn't follow the changes you are
> actually aiming to do here.
>

Actually in dp_compute_config(), we just compute the optimum port_clock
selected from the common_rates array. We dont really use rate_select or link_bw here
in this function. These two parameters get used directly in the clock_recovery
where we either write rate_select or link_bw to the dpcd link config registers.
So by removing this call to intel_dp_compute_rate() from compute_config() makes sense
to me. And it does not alter the eDP compute config behaviour.

However I think to be clear, the above explanation needs to be included in th commit message.
With that included,

Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>

Manasi 
> > -
> > -	DRM_DEBUG_KMS("DP link bw %02x rate select %02x lane count %d clock %d bpp %d\n",
> > -		      link_bw, rate_select, pipe_config->lane_count,
> > -		      pipe_config->port_clock, bpp);
> > +	DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n",
> > +		      pipe_config->lane_count, pipe_config->port_clock, bpp);
> >  	DRM_DEBUG_KMS("DP link bw required %i available %i\n",
> >  		      mode_rate, link_avail);
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
> > index f59b59bb0a21..3fcaa98b9055 100644
> > --- a/drivers/gpu/drm/i915/intel_dp_link_training.c
> > +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
> > @@ -139,6 +139,11 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
> >  	intel_dp_compute_rate(intel_dp, intel_dp->link_rate,
> >  			      &link_bw, &rate_select);
> >  
> > +	if (link_bw)
> > +		DRM_DEBUG_KMS("Using LINK_BW_SET value %02x\n", link_bw);
> > +	else
> > +		DRM_DEBUG_KMS("Using LINK_RATE_SET value %02x\n", rate_select);
> > +
> >  	/* Write the link configuration data */
> >  	link_config[0] = link_bw;
> >  	link_config[1] = intel_dp->lane_count;
> > -- 
> > 2.11.0
> > 
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