[Intel-gfx] [PATCH 2/2] drm/i915: Simplify scaler init during CRTC HW readout

[Imre Deak]

On Fri, Jul 21, 2017 at 06:44:24PM +0530, Mahesh Kumar wrote:
> Hi,
> 
> 
> On Thursday 20 July 2017 04:20 AM, Imre Deak wrote:
> > The crtc state starts out being bzero'd, so no need to clear
> > scaler_users. Also intel_crtc_init_scalers() knows already which
> > platforms have scalers, so no need for the platform check here.
> > Similarly intel_crtc_init_scalers() will init scaler_id as required,
> > so no need to do it here separately.
> > 
> > Cc: Chandra Konduru <chandra.konduru at intel.com>
> > Cc: Matt Roper <matthew.d.roper at intel.com>
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >   drivers/gpu/drm/i915/intel_display.c | 7 +------
> >   1 file changed, 1 insertion(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 8a38e64b1931..7210f418e9c0 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -9132,12 +9132,7 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
> >   	u64 power_domain_mask;
> >   	bool active;
> > -	if (INTEL_GEN(dev_priv) >= 9) {
> > -		intel_crtc_init_scalers(crtc, pipe_config);
> > -
> > -		pipe_config->scaler_state.scaler_id = -1;
> > -		pipe_config->scaler_state.scaler_users &= ~(1 << SKL_CRTC_INDEX);
> > -	}
> > +	intel_crtc_init_scalers(crtc, pipe_config);
> If we are removing gen check, then IMHO we should initialize "scaler_id =
> -1" even before !crtc->num_scalers check in intel_crtc_init_scalers
> function, just to make sure scaler state doesn't have wrong value in
> platforms where we don't have any scalers.

I agree that setting scaler_id to -1 on all platforms is a good idea,
but it's unrelated to removing here the GEN check. intel_crtc_init_scalers()
is already called for all platforms in intel_crtc_init(). So this change won't
make a difference for platforms without scalers: we leave scaler_id zeroed
on those already now (they have num_scalers set to 0). This isn't either
a problem since we allocate scalers only on GEN9+.

So we could do what you suggest but imo as a follow-up.

--Imre