Re: [PATCH 04/12] drm/i915/psr: Tie PSR2 support to Y coordinate requirement

["Souza, Jose" <jose.souza@intel.com>]

On Thu, 2018-03-22 at 16:09 -0700, Rodrigo Vivi wrote:
> On Thu, Mar 22, 2018 at 02:48:40PM -0700, José Roberto de Souza
> wrote:
> > Move to only one place the sink requirements that the actual driver
> > needs to enable PSR2.
> > 
> > Also intel_psr2_config_valid() is called every time the crtc config
> > is computed, wasting some time every time it was checking for
> > Y coordinate requirement.
> > 
> > This allow us to nuke y_cord_support and some of VSC setup code
> > that
> > was handling a scenario that would never happen(PSR2 without Y
> > coordinate).
> > 
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h  |  1 -
> >  drivers/gpu/drm/i915/intel_psr.c | 46 +++++++++++++++++-----------
> > ------------
> >  2 files changed, 19 insertions(+), 28 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> > b/drivers/gpu/drm/i915/i915_drv.h
> > index 7fe00509e51a..cce32686fd75 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -603,7 +603,6 @@ struct i915_psr {
> >  	unsigned busy_frontbuffer_bits;
> >  	bool psr2_support;
> >  	bool link_standby;
> > -	bool y_cord_support;
> >  	bool colorimetry_support;
> >  	bool alpm;
> >  	bool has_hw_tracking;
> > diff --git a/drivers/gpu/drm/i915/intel_psr.c
> > b/drivers/gpu/drm/i915/intel_psr.c
> > index d46320a451d9..23f38ab10636 100644
> > --- a/drivers/gpu/drm/i915/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/intel_psr.c
> > @@ -93,7 +93,7 @@ static void psr_aux_io_power_put(struct intel_dp
> > *intel_dp)
> >  	intel_display_power_put(dev_priv,
> > psr_aux_domain(intel_dp));
> >  }
> >  
> > -static bool intel_dp_get_y_cord_status(struct intel_dp *intel_dp)
> > +static bool intel_dp_get_y_coord_required(struct intel_dp
> > *intel_dp)
> 
> nip: I don't agree that required is a good name for this function
> call
> so maybe we should just leave status and minimize the change.

This is the name in the eDP spec: Y-coordinate Requirement of Sink
Device on PSR2 Selective Update

> 
> >  {
> >  	uint8_t psr_caps = 0;
> >  
> > @@ -130,22 +130,29 @@ void intel_psr_init_dpcd(struct intel_dp
> > *intel_dp)
> >  	drm_dp_dpcd_read(&intel_dp->aux, DP_PSR_SUPPORT, intel_dp-
> > >psr_dpcd,
> >  			 sizeof(intel_dp->psr_dpcd));
> >  
> > -	if (intel_dp->psr_dpcd[0] & DP_PSR_IS_SUPPORTED) {
> > +	if (intel_dp->psr_dpcd[0]) {
> 
> hm? why?

A pannel that is PSR version 2, will not have any PSR enabled as
'intel_dp->psr_dpcd[0] & DP_PSR_IS_SUPPORTED' and 'intel_dp-
>psr_dpcd[0] == DP_PSR2_WITH_Y_COORD_IS_SUPPORTED' will be false.

> 
> >  		dev_priv->psr.sink_support = true;
> >  		DRM_DEBUG_KMS("Detected EDP PSR Panel.\n");
> >  	}
> >  
> >  	if (INTEL_GEN(dev_priv) >= 9 &&
> > -	    (intel_dp->psr_dpcd[0] & DP_PSR2_IS_SUPPORTED)) {
> > -
> > -		dev_priv->psr.sink_support = true;
> > -		dev_priv->psr.psr2_support = true;
> > +	    (intel_dp->psr_dpcd[0] ==
> > DP_PSR2_WITH_Y_COORD_IS_SUPPORTED)) {
> > +		/*
> > +		 * All panels that supports PSR version 03h (PSR2
> > +
> > +		 * Y-coordinate) can handle Y-coordinates in VSC
> > but we are
> > +		 * only sure that it is going to be used when
> > required by the
> > +		 * panel. This way panel is capable to do
> > selective update
> > +		 * without a aux frame sync.
> > +		 *
> > +		 * To support PSR version 02h and PSR version 03h
> > without
> > +		 * Y-coordinate requirement panels we would need
> > to enable
> > +		 * GTC first.
> > +		 */
> > +		dev_priv->psr.psr2_support =
> > intel_dp_get_y_coord_required(intel_dp);
> 
> oh ok ok... now I saw why you changed to "required"
> 
> But my question now is. Do we really need to check this bit?
> 
> I believe with your change to check version 03h we don't need to
> check
> this requirement anymore.
> This looks like in the past we used that to workaround a way to
> identify
> if the panel was really y-coord... but now with 03h version we don't
> need
> to check if panel is requiring the y-coordination from the source,
> because
> we know what source is capable of.

We know that is capable of but we don't know if is going to be used by
the pannel, when pannels require the y-coordinate we are 100% sure that
it is going to use.

> 
> >  		DRM_DEBUG_KMS("PSR2 %s on sink",
> >  			      dev_priv->psr.psr2_support ?
> > "supported" : "not supported");
> >  
> >  		if (dev_priv->psr.psr2_support) {
> > -			dev_priv->psr.y_cord_support =
> > -				intel_dp_get_y_cord_status(intel_d
> > p);
> >  			dev_priv->psr.colorimetry_support =
> >  				intel_dp_get_colorimetry_status(in
> > tel_dp);
> >  			dev_priv->psr.alpm =
> > @@ -191,16 +198,12 @@ static void hsw_psr_setup_vsc(struct intel_dp
> > *intel_dp,
> >  		memset(&psr_vsc, 0, sizeof(psr_vsc));
> >  		psr_vsc.sdp_header.HB0 = 0;
> >  		psr_vsc.sdp_header.HB1 = 0x7;
> > -		if (dev_priv->psr.colorimetry_support &&
> > -		    dev_priv->psr.y_cord_support) {
> > +		if (dev_priv->psr.colorimetry_support) {
> >  			psr_vsc.sdp_header.HB2 = 0x5;
> >  			psr_vsc.sdp_header.HB3 = 0x13;
> > -		} else if (dev_priv->psr.y_cord_support) {
> > +		} else {
> >  			psr_vsc.sdp_header.HB2 = 0x4;
> >  			psr_vsc.sdp_header.HB3 = 0xe;
> > -		} else {
> > -			psr_vsc.sdp_header.HB2 = 0x3;
> > -			psr_vsc.sdp_header.HB3 = 0xc;
> >  		}
> >  	} else {
> >  		/* Prepare VSC packet as per EDP 1.3 spec, Table
> > 3.10 */
> > @@ -458,15 +461,6 @@ static bool intel_psr2_config_valid(struct
> > intel_dp *intel_dp,
> >  		return false;
> >  	}
> >  
> > -	/*
> > -	 * FIXME:enable psr2 only for y-cordinate psr2 panels
> > -	 * After gtc implementation , remove this restriction.
> > -	 */
> > -	if (!dev_priv->psr.y_cord_support) {
> > -		DRM_DEBUG_KMS("PSR2 not enabled, panel does not
> > support Y coordinate\n");
> > -		return false;
> > -	}
> > -
> >  	return true;
> >  }
> >  
> > @@ -566,7 +560,6 @@ static void hsw_psr_enable_source(struct
> > intel_dp *intel_dp,
> >  	struct drm_device *dev = dig_port->base.base.dev;
> >  	struct drm_i915_private *dev_priv = to_i915(dev);
> >  	enum transcoder cpu_transcoder = crtc_state-
> > >cpu_transcoder;
> > -	u32 chicken;
> >  
> >  	psr_aux_io_power_get(intel_dp);
> >  
> > @@ -577,9 +570,8 @@ static void hsw_psr_enable_source(struct
> > intel_dp *intel_dp,
> >  		hsw_psr_setup_aux(intel_dp);
> >  
> >  	if (dev_priv->psr.psr2_support) {
> > -		chicken = PSR2_VSC_ENABLE_PROG_HEADER;
> > -		if (dev_priv->psr.y_cord_support)
> > -			chicken |= PSR2_ADD_VERTICAL_LINE_COUNT;
> > +		u32 chicken = PSR2_VSC_ENABLE_PROG_HEADER
> > +			      | PSR2_ADD_VERTICAL_LINE_COUNT;
> >  		I915_WRITE(CHICKEN_TRANS(cpu_transcoder),
> > chicken);
> >  
> >  		I915_WRITE(EDP_PSR_DEBUG,
> > -- 
> > 2.16.2
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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