[Intel-gfx] [PATCH 14/21] drm/i915: use current scaler state during readout_hw_state.

[Konduru, Chandra]

> -----Original Message-----
> From: Daniel Vetter [mailto:daniel.vetter at ffwll.ch] On Behalf Of Daniel Vetter
> Sent: Tuesday, March 17, 2015 7:20 AM
> To: Konduru, Chandra
> Cc: intel-gfx at lists.freedesktop.org; Conselvan De Oliveira, Ander; Vetter, Daniel
> Subject: Re: [Intel-gfx] [PATCH 14/21] drm/i915: use current scaler state during
> readout_hw_state.
> 
> On Sat, Mar 14, 2015 at 10:55:39PM -0700, Chandra Konduru wrote:
> > During readout_hw_state, whole pipe_config is built reading hw.
> > But rebuilding scaler state from hw requires,
> >  - reading all planes and find its corresponding index in order to set
> >    its bits in scaler_users
> >  - reading cdclk and adjusted mode crtc clk in order to regenerate
> >    min scaling ratios.
> >  - some values directly from bspec
> >
> > To simplify things, for now using sw scaler state as readout state.
> >
> > Signed-off-by: Chandra Konduru <chandra.konduru at intel.com>
> 
> At least the crtc scaler might get used by the bios for boot-up with non-native
> resolution. I do think we need to properly track those parts (and also double-
> check the hw state in pipe config compare function like we do for the old pfit
> state).

To cover above case, will populate the crtc scaler state.

But population of scalers used for planes is tricky, because 
in general there is no population of planes or its states from hw.
>From scaler point of this may be ok because there aren't any 
scalers in use for planes.

> 
> Maybe we need to always compute limits directly instead of storing the in the
> state structures?

We are adjusting/computing some of limits from hw but not all
limits. 
Along with crtc_scaler population, will add code to populate
limits that can be computed from hw. Rest will carry from previous
state.

> -Daniel
> 
> > ---
> >  drivers/gpu/drm/i915/intel_display.c |    3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > index 9c3c6b1..b1d7036 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -14292,7 +14292,10 @@ static void
> intel_modeset_readout_hw_state(struct drm_device *dev)
> >  	int i;
> >
> >  	for_each_intel_crtc(dev, crtc) {
> > +		struct intel_crtc_scaler_state scaler_state;
> > +		scaler_state = crtc->config->scaler_state;
> >  		memset(crtc->config, 0, sizeof(*crtc->config));
> > +		crtc->config->scaler_state = scaler_state;
> >
> >  		crtc->config->quirks |=
> PIPE_CONFIG_QUIRK_INHERITED_MODE;
> >
> > --
> > 1.7.9.5
> >
> > _______________________________________________
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> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch