[Intel-gfx] [PATCH 1/2] drm/i915: Fix scaler init during CRTC HW state readout

[Imre Deak]

On Thu, Jul 20, 2017 at 11:58:35AM +0300, Jani Nikula wrote:
> On Thu, 20 Jul 2017, Imre Deak <imre.deak at intel.com> wrote:
> > The scaler allocation code depends on a non-zero default value for the
> > crtc scaler_id, so make sure we initialize the scaler state accordingly
> > even if the crtc is off. This fixes at least an initial YUV420 modeset
> > (added in a follow-up patchset by Shashank) when booting with the screen
> > off: after the initial HW readout and modeset which enables the scaler a
> > subsequent modeset will disable the scaler which isn't properly
> > allocated. This results in a funky HW state where the pipe scaler HW
> > registers can't be modified and the normally black screen is grey and
> > shifted to the right or jitters.
> >
> > The problem was revealed by Shashank's YUV420 patchset and first
> > reported by Ville.
> >
> > Cc: Shashank Sharma <shashank.sharma at intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Chandra Konduru <chandra.konduru at intel.com>
> > Cc: Matt Roper <matthew.d.roper at intel.com>
> > Cc: <stable at vger.kernel.org> # 4.11.x
> > Reported-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Fixes: a1b2278e4dfc ("drm/i915: skylake panel fitting using shared scalers")
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> >
> > ---
> >
> > [ Older stable versions need backporting, so that's for a follow-up ]
> 
> I thought we'd annotate cc: stable with all the kernels that need the
> fix, not according to where the fix applies as-is. In this case, it
> would be v4.2+, right?

Hm, not sure. I know that this won't apply before 4.11 and I will have
to send a backported version anyway. So wanted to save a redundant turn
around after the automatic cherry picking to those stable versions
fail.

Greg, what's the proper tag in this case?

Thanks,
Imre

> 
> BR,
> Jani.
> 
> 
> 
> > ---
> >  drivers/gpu/drm/i915/intel_display.c | 14 +++++++-------
> >  1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 7774f3465fbc..8a38e64b1931 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -9132,6 +9132,13 @@ 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);
> > +	}
> > +
> >  	power_domain = POWER_DOMAIN_PIPE(crtc->pipe);
> >  	if (!intel_display_power_get_if_enabled(dev_priv, power_domain))
> >  		return false;
> > @@ -9160,13 +9167,6 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
> >  	pipe_config->gamma_mode =
> >  		I915_READ(GAMMA_MODE(crtc->pipe)) & GAMMA_MODE_MODE_MASK;
> >  
> > -	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);
> > -	}
> > -
> >  	power_domain = POWER_DOMAIN_PIPE_PANEL_FITTER(crtc->pipe);
> >  	if (intel_display_power_get_if_enabled(dev_priv, power_domain)) {
> >  		power_domain_mask |= BIT_ULL(power_domain);
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center