[Intel-gfx] [v2 2/2] drm/i915/icl: Fix port disable sequence for mipi-dsi

[Kulkarni, Vandita]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: Friday, March 22, 2019 8:02 PM
> To: Kulkarni, Vandita <vandita.kulkarni at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; Nikula, Jani <jani.nikula at intel.com>
> Subject: Re: [Intel-gfx] [v2 2/2] drm/i915/icl: Fix port disable sequence for mipi-
> dsi
> 
> On Fri, Mar 22, 2019 at 05:43:52PM +0530, Vandita Kulkarni wrote:
> > Re-enable clock gating of DDI clocks.
> >
> > v2: Fix the default ddi clk state for mipi-dsi (Imre)
> >
> > Fixes: 1026bea00381 (drm/i915/icl: Ungate DSI clocks)
> > Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
> > ---
> >  drivers/gpu/drm/i915/icl_dsi.c   | 2 +-
> >  drivers/gpu/drm/i915/intel_ddi.c | 6 +++---
> >  2 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/icl_dsi.c
> > b/drivers/gpu/drm/i915/icl_dsi.c index 6a5b9fa..5caf41f 100644
> > --- a/drivers/gpu/drm/i915/icl_dsi.c
> > +++ b/drivers/gpu/drm/i915/icl_dsi.c
> > @@ -1124,7 +1124,7 @@ static void gen11_dsi_disable_port(struct
> intel_encoder *encoder)
> >  			DRM_ERROR("DDI port:%c buffer not idle\n",
> >  				  port_name(port));
> >  	}
> > -	gen11_dsi_ungate_clocks(encoder);
> > +	gen11_dsi_gate_clocks(encoder);
> >  }
> >
> >  static void gen11_dsi_disable_io_power(struct intel_encoder *encoder)
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c
> > b/drivers/gpu/drm/i915/intel_ddi.c
> > index 933df3a..17a03fa 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -2821,10 +2821,10 @@ void icl_sanitize_encoder_pll_mapping(struct
> intel_encoder *encoder)
> >  				return;
> >  		}
> >  		/*
> > -		 * DSI ports should have their DDI clock ungated when disabled
> > -		 * and gated when enabled.
> > +		 * For MIPI DSI we unagate the clocks later as part of
> > +		 * enable sequence. Keep them gated by default.
> >  		 */
> > -		ddi_clk_needed = !encoder->base.crtc;
> > +		ddi_clk_needed = false;
> 
> Should that be true?
No. False. 
We are comparing ddi_clk_needed with clock ungated which is false for mipi dsi. 
So we do nothing in this function if it is already gated, and gate it if we have ungated = true.

Regards,
Vandita

> 
> >  	}
> >
> >  	val = I915_READ(DPCLKA_CFGCR0_ICL);
> > --
> > 1.9.1
> >
> > _______________________________________________
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> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> --
> Ville Syrjälä
> Intel