[PATCH] drm/i915/pps: Disable DPLS_GATING around pps sequence

[Kandpal, Suraj]

> -----Original Message-----
> From: Bhadane, Dnyaneshwar <dnyaneshwar.bhadane at intel.com>
> Sent: Monday, July 29, 2024 7:24 PM
> To: Kandpal, Suraj <suraj.kandpal at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Golani, Mitulkumar Ajitkumar <mitulkumar.ajitkumar.golani at intel.com>;
> Kandpal, Suraj <suraj.kandpal at intel.com>
> Subject: RE: [PATCH] drm/i915/pps: Disable DPLS_GATING around pps sequence
> 
> 
> 
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of
> > Suraj Kandpal
> > Sent: Thursday, May 9, 2024 8:59 AM
> > To: intel-gfx at lists.freedesktop.org
> > Cc: Golani, Mitulkumar Ajitkumar
> > <mitulkumar.ajitkumar.golani at intel.com>;
> > Kandpal, Suraj <suraj.kandpal at intel.com>
> > Subject: [PATCH] drm/i915/pps: Disable DPLS_GATING around pps sequence
> >
> > Disable bit 29 of SCLKGATE_DIS register around pps sequence when we
> > turn panel power on.
> >
> > --v2
> > -Squash two commit together [Jani]
> > -Use IS_DISPLAY_VER [Jani]
> > -Fix multiline comment [Jani]
> >
> > --v3
> > -Define register in a more appropriate place [Mitul]
> >
> > Bspec: 49304
> > Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_pps.c | 12 ++++++++++++
> >  drivers/gpu/drm/i915/i915_reg.h          |  4 ++++
> >  2 files changed, 16 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_pps.c
> > b/drivers/gpu/drm/i915/display/intel_pps.c
> > index 0ccbf9a85914..d774aeb1673e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_pps.c
> > +++ b/drivers/gpu/drm/i915/display/intel_pps.c
> > @@ -948,6 +948,14 @@ void intel_pps_on_unlocked(struct intel_dp
> *intel_dp)
> >  		intel_de_posting_read(dev_priv, pp_ctrl_reg);
> >  	}
> >
> > +	/*
> Hi Suraj,
> > +	 * WA: 16023567976
>  --------------------^^^^^^^^ is not the correct WA number.
> Please mention the linage number here.
> 
> > +	 * Disable DPLS gating around power sequence.
> > +	 */
> > +	if (IS_DISPLAY_VER(dev_priv, 12, 14))
> 
> Also, I did not find the link to the display version 12 for this WA.
> I could see the target display version for this WA is 13.00 and 14.00 as a
> permanent WA for now.
> 

Not sure how you checked this but if you go to the WA number it clearly states
Family affected as : Display 12,13,14

Regards,
Suraj Kandpal
> Dnyaneshwar
> 
> > +		intel_de_rmw(dev_priv, SCLKGATE_DIS,
> > +			     0, DPLS_GATING_DISABLE);
> > +
> >  	pp |= PANEL_POWER_ON;
> >  	if (!IS_IRONLAKE(dev_priv))
> >  		pp |= PANEL_POWER_RESET;
> > @@ -958,6 +966,10 @@ void intel_pps_on_unlocked(struct intel_dp
> *intel_dp)
> >  	wait_panel_on(intel_dp);
> >  	intel_dp->pps.last_power_on = jiffies;
> >
> > +	if (IS_DISPLAY_VER(dev_priv, 12, 14))
> > +		intel_de_rmw(dev_priv, SCLKGATE_DIS,
> > +			     DPLS_GATING_DISABLE, 0);
> > +
> >  	if (IS_IRONLAKE(dev_priv)) {
> >  		pp |= PANEL_POWER_RESET; /* restore panel reset bit */
> >  		intel_de_write(dev_priv, pp_ctrl_reg, pp); diff --git
> > a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 5670eee4a498..4cc82360298b 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -5151,6 +5151,10 @@ enum skl_power_gate {
> >
> >  #define _MMIO_PLANE_GAMC(plane, i, a, b)  _MMIO(_PIPE(plane, a, b) +
> > (i) * 4)
> >
> > +/* SCLKGATE_DIS */
> > +#define SCLKGATE_DIS			_MMIO(0xc2020)
> > +#define  DPLS_GATING_DISABLE		REG_BIT(29)
> > +
> >  /* Plane CSC Registers */
> >  #define _PLANE_CSC_RY_GY_1_A	0x70210
> >  #define _PLANE_CSC_RY_GY_2_A	0x70310
> > --
> > 2.43.2