[Intel-gfx] [GLK MIPI DSI V3 4/7] drm/i915: Set the Z inversion overlap field

[Chauhan, Madhav]

> -----Original Message-----
> From: Nikula, Jani
> Sent: Wednesday, January 18, 2017 9:21 PM
> To: Chauhan, Madhav <madhav.chauhan at intel.com>; intel-
> gfx at lists.freedesktop.org
> Cc: Shankar, Uma <uma.shankar at intel.com>; Mukherjee, Indranil
> <indranil.mukherjee at intel.com>; Kamath, Sunil <sunil.kamath at intel.com>;
> Saarinen, Jani <jani.saarinen at intel.com>; Conselvan De Oliveira, Ander
> <ander.conselvan.de.oliveira at intel.com>; Konduru, Chandra
> <chandra.konduru at intel.com>; Kumar, Shobhit
> <shobhit.kumar at intel.com>; Syrjala, Ville <ville.syrjala at intel.com>; Deepak
> M <m.deepak at intel.com>; Chauhan, Madhav
> <madhav.chauhan at intel.com>
> Subject: Re: [GLK MIPI DSI V3 4/7] drm/i915: Set the Z inversion overlap field
> 
> On Mon, 02 Jan 2017, Madhav Chauhan <madhav.chauhan at intel.com>
> wrote:
> > From: Deepak M <m.deepak at intel.com>
> >
> > Dual link Z-inversion overlap field is present in MIPI_CTRL register
> > unlike the older platforms, hence setting the same in this patch.
> >
> > Signed-off-by: Deepak M <m.deepak at intel.com>
> > Signed-off-by: Madhav Chauhan <madhav.chauhan at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dsi.c | 17 +++++++++++++----
> >  1 file changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_dsi.c
> > b/drivers/gpu/drm/i915/intel_dsi.c
> > index 3ae70ae..95a6cad 100644
> > --- a/drivers/gpu/drm/i915/intel_dsi.c
> > +++ b/drivers/gpu/drm/i915/intel_dsi.c
> > @@ -558,12 +558,21 @@ static void intel_dsi_port_enable(struct
> > intel_encoder *encoder)
> >
> >  	if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
> >  		u32 temp;
> > -
> > -		temp = I915_READ(VLV_CHICKEN_3);
> > -		temp &= ~PIXEL_OVERLAP_CNT_MASK |
> > +		if (IS_GEN9_LP(dev_priv)) {
> > +			for_each_dsi_port(port, intel_dsi->ports) {
> > +				temp = I915_READ(MIPI_CTRL(port));
> > +				temp &= ~BXT_PIXEL_OVERLAP_CNT_MASK |
> > +					intel_dsi->pixel_overlap <<
> > +					BXT_PIXEL_OVERLAP_CNT_SHIFT;
> > +				I915_WRITE(MIPI_CTRL(port), temp);
> 
> I think I'd do this where MIPI_CTRL is updated. If we set

What to do when MIPI_CTRL is updated and where?? Please specify.

> ->pixel_overlap to 0 for intel_dsi->dual_link !=
> DSI_DUAL_LINK_FRONT_BACK in vbt_panel_init(), we can just write it instead
> of checking dual_link.

Yes we can do this but any way we need to put if condition inside vbt_panel_init. Additional advantage??
It would be more useful if we replace all if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK)  checks inside the driver code 
When ->pixel_overlap is used. Am I missing something?? Please clarify.

> 
> BR,
> Jani.
> 
> > +			}
> > +		} else {
> > +			temp = I915_READ(VLV_CHICKEN_3);
> > +			temp &= ~PIXEL_OVERLAP_CNT_MASK |
> >  					intel_dsi->pixel_overlap <<
> >  					PIXEL_OVERLAP_CNT_SHIFT;
> > -		I915_WRITE(VLV_CHICKEN_3, temp);
> > +			I915_WRITE(VLV_CHICKEN_3, temp);
> > +		}
> >  	}
> >
> >  	for_each_dsi_port(port, intel_dsi->ports) {
> 
> --
> Jani Nikula, Intel Open Source Technology Center