[Intel-gfx] [PATCH 7/8] drm/i915/psr: Don't tell sink that main link will be active in PSR2

[Souza, Jose]

On Mon, 2018-09-24 at 23:02 -0700, dhinakaran.pandiyan at gmail.com wrote:
> On Thu, 2018-09-20 at 13:43 -0700, José Roberto de Souza wrote:
> > For PSR2 we don't have the option to keep main link enabled while
> > PSR2 is active, so don't configure sink DPCD with a wrong value.
> 
> Is this what the DP spec says or an Intel HW restriction?

This is Intel HW restriction as there is no register in PSR2 CTL to
keep link in standby, DP spec states that link can be kept on or off
while PSR2 is active, there is just a new timming restriction to turn
link off.

> 
> -DK
> 
> > 
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>s
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_psr.c | 9 +++++----
> >  1 file changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_psr.c
> > b/drivers/gpu/drm/i915/intel_psr.c
> > index cf9d6e965697..60cf6fd251d0 100644
> > --- a/drivers/gpu/drm/i915/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/intel_psr.c
> > @@ -344,12 +344,13 @@ static void intel_psr_enable_sink(struct
> > intel_dp *intel_dp)
> >  		drm_dp_dpcd_writeb(&intel_dp->aux,
> > DP_RECEIVER_ALPM_CONFIG,
> >  				   DP_ALPM_ENABLE);
> >  		dpcd_val |= DP_PSR_ENABLE_PSR2 |
> > DP_PSR_IRQ_HPD_WITH_CRC_ERRORS;
> > +	} else {
> > +		if (dev_priv->psr.link_standby)
> > +			dpcd_val |= DP_PSR_MAIN_LINK_ACTIVE;
> > +		if (INTEL_GEN(dev_priv) >= 8)
> > +			dpcd_val |= DP_PSR_CRC_VERIFICATION;
> >  	}
> >  
> > -	if (dev_priv->psr.link_standby)
> > -		dpcd_val |= DP_PSR_MAIN_LINK_ACTIVE;
> > -	if (!dev_priv->psr.psr2_enabled && INTEL_GEN(dev_priv) >= 8)
> > -		dpcd_val |= DP_PSR_CRC_VERIFICATION;
> >  	drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, dpcd_val);
> >  
> >  	drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
> > DP_SET_POWER_D0);