[PATCH] drm/i915/display: Add WA_14018221282

[Garg, Nemesa]

> -----Original Message-----
> From: Golani, Mitulkumar Ajitkumar <mitulkumar.ajitkumar.golani at intel.com>
> Sent: Friday, November 8, 2024 1:47 PM
> To: Garg, Nemesa <nemesa.garg at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Garg, Nemesa <nemesa.garg at intel.com>; Kulkarni at freedesktop.org;
> Kulkarni, Vandita <vandita.kulkarni at intel.com>
> Subject: RE: [PATCH] drm/i915/display: Add WA_14018221282
> 
> 
> 
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of
> > Nemesa Garg
> > Sent: 08 November 2024 13:31
> > To: intel-gfx at lists.freedesktop.org
> > Cc: Garg, Nemesa <nemesa.garg at intel.com>; Kulkarni at freedesktop.org;
> > Kulkarni, Vandita <vandita.kulkarni at intel.com>
> > Subject: [PATCH] drm/i915/display: Add WA_14018221282
> >
> > It was observed that the first write to DKL DP Mode register was not
> > taking effect, hence rewrite this register.
> >
> > Signed-off-by: Nemesa Garg <nemesa.garg at intel.com>
> > Signed-off-by: Kulkarni, Vandita <vandita.kulkarni at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_ddi.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> > b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index 769bd1f26db2..16a1d18f3aa1 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -2104,6 +2104,16 @@ void
> > intel_ddi_sanitize_encoder_pll_mapping(struct intel_encoder *encoder)
> >  	encoder->disable_clock(encoder);
> >  }
> >
> > +static void
> > +tgl_wa_14018221282(struct drm_i915_private *dev_priv, enum tc_port
> > tc_port,
> 
> 1. I recommend, Need to think on naming here, as doesn't clarify on anything.
Sure will rename it.
> 2. Also adding on thought to have pre-check of return if values are already
> updated.
I guess return is not required because before writing the values I am checking whether
values are updated or not, then only writing the values.
> 
> > +		   u32 ln0, u32 ln1)
> > +{
> > +	if (ln0 != intel_dkl_phy_read(dev_priv, DKL_DP_MODE(tc_port, 0)))
> > +		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 0),
> > ln0);
> > +	if (ln1 != intel_dkl_phy_read(dev_priv, DKL_DP_MODE(tc_port, 1)))
> > +		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 1),
> > ln1); }
> > +
> >  static void
> >  icl_program_mg_dp_mode(struct intel_digital_port *dig_port,
> >  		       const struct intel_crtc_state *crtc_state) @@ -2185,6
> > +2195,10 @@ icl_program_mg_dp_mode(struct intel_digital_port
> > +*dig_port,
> >  	if (DISPLAY_VER(dev_priv) >= 12) {
> >  		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 0), ln0);
> >  		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 1), ln1);
> > +		 /* WA_14018221282 */
> > +		if (DISPLAY_VER(dev_priv) == 12)
> > +			tgl_wa_14018221282(dev_priv, tc_port, ln0, ln1);
> 
> Always use the display local var when possible. DISPLAY_VER(display)
Sure will do.
> 
> > +
> >  	} else {
> >  		intel_de_write(dev_priv, MG_DP_MODE(0, tc_port), ln0);
> >  		intel_de_write(dev_priv, MG_DP_MODE(1, tc_port), ln1);
> > --
> > 2.25.1