Re: [Intel-gfx] [PATCH v3 1/3] drm/i915/display: Program PIPE_MBUS_DBOX_CTL with adl-p values

["Sripada, Radhakrishna" <radhakrishna.sripada@intel.com>]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of José
> Roberto de Souza
> Sent: Tuesday, March 29, 2022 12:46 AM
> To: intel-gfx@lists.freedesktop.org
> Cc: Nikula, Jani <jani.nikula@intel.com>
> Subject: [Intel-gfx] [PATCH v3 1/3] drm/i915/display: Program
> PIPE_MBUS_DBOX_CTL with adl-p values
> 
> From: Caz Yokoyama <caz.yokoyama@intel.com>
> 
> B credits set by IFWI do not match with specification default, so here
> programming the right value.
> 
> Also while at it, taking the oportunity to do a read-modify-write to
> not overwrite all other bits in this register that specification don't
> ask us to change.
> 
> BSpec: 49213
> BSpec: 50343
> Cc: Matt Roper <matthew.d.roper@intel.com>
> Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>


> Signed-off-by: Caz Yokoyama <caz.yokoyama@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> b/drivers/gpu/drm/i915/display/intel_display.c
> index 3d2ff258f0a94..078ada041e1cd 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -1830,13 +1830,19 @@ static void icl_pipe_mbus_enable(struct intel_crtc
> *crtc, bool joined_mbus)
>  	enum pipe pipe = crtc->pipe;
>  	u32 val;
> 
> +	val = intel_de_read(dev_priv, PIPE_MBUS_DBOX_CTL(pipe));
> +	val &= ~MBUS_DBOX_A_CREDIT_MASK;
>  	/* Wa_22010947358:adl-p */
>  	if (IS_ALDERLAKE_P(dev_priv))
> -		val = joined_mbus ? MBUS_DBOX_A_CREDIT(6) :
> MBUS_DBOX_A_CREDIT(4);
> +		val |= joined_mbus ? MBUS_DBOX_A_CREDIT(6) :
> MBUS_DBOX_A_CREDIT(4);
>  	else
> -		val = MBUS_DBOX_A_CREDIT(2);
> +		val |= MBUS_DBOX_A_CREDIT(2);
> 
> -	if (DISPLAY_VER(dev_priv) >= 12) {
> +	val &= ~(MBUS_DBOX_BW_CREDIT_MASK |
> MBUS_DBOX_B_CREDIT_MASK);
> +	if (IS_ALDERLAKE_P(dev_priv)) {
> +		val |= MBUS_DBOX_BW_CREDIT(2);
> +		val |= MBUS_DBOX_B_CREDIT(8);
> +	} else if (DISPLAY_VER(dev_priv) >= 12) {
>  		val |= MBUS_DBOX_BW_CREDIT(2);
>  		val |= MBUS_DBOX_B_CREDIT(12);
>  	} else {
> --
> 2.35.1