[PATCH] drm/i915/display: Add WA_14018221282

[Golani, Mitulkumar Ajitkumar]

> -----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.
2. Also adding on thought to have pre-check of return if values are already updated.

> +		   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)

> +
>  	} 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