[PATCH] drm/i915/hdcp: Disable HDCP Line Rekeying for HDCP2.2 on HDMI

[Borah, Chaitanya Kumar]

Hello Suraj,

> -----Original Message-----
> From: Kandpal, Suraj <suraj.kandpal at intel.com>
> Sent: Wednesday, April 17, 2024 3:26 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Borah, Chaitanya Kumar <chaitanya.kumar.borah at intel.com>; Shankar,
> Uma <uma.shankar at intel.com>; Nautiyal, Ankit K
> <ankit.k.nautiyal at intel.com>; Nikula, Jani <jani.nikula at intel.com>; Kandpal,
> Suraj <suraj.kandpal at intel.com>
> Subject: [PATCH] drm/i915/hdcp: Disable HDCP Line Rekeying for HDCP2.2 on
> HDMI
> 
> Disable HDCP Line Rekeying when HDCP ver > 1.4 and when we are on HDMI
> TMDS operation for DISPLAY_VER >= 14.
> 
> --v2
> -Wa to be mentioned in comments not in commit message [Jani] -Remove
> blankline [Jani]
> 
> --v3
> -No need to write what is being done in comments when code is self
> explanatory [Jani]
> 
> Bspec: 49273
> Bspec: 69964
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hdcp.c | 17 +++++++++++++++++
>  drivers/gpu/drm/i915/i915_reg.h           |  1 +
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c
> b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index d5ed4c7dfbc0..78b20f23a2e1 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -30,6 +30,21 @@
>  #define KEY_LOAD_TRIES	5
>  #define HDCP2_LC_RETRY_CNT			3
> 
> +/* WA: 16022217614 */
> +static void
> +intel_hdcp_disable_hdcp_line_rekeying(struct intel_encoder *encoder,
> +				      struct intel_hdcp *hdcp)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +
> +	if (encoder->type != INTEL_OUTPUT_HDMI)
> +		return;

(Nit) Though we can't do much here for non-TMDS HDMI, we can keep a comment so that if such support is added in future, there is a hint to make the change.

> +
> +	if (DISPLAY_VER(dev_priv) >= 14)
> +		intel_de_rmw(dev_priv, TRANS_DDI_FUNC_CTL(hdcp-
> >cpu_transcoder),

This register seems to differ for MTL and BMG. Kindly re-check.

Regards

Chaitanya

> +			     TRANS_DDI_HDCP_LINE_REKEY_DISABLE, 1); }
> +
>  static int intel_conn_to_vcpi(struct intel_atomic_state *state,
>  			      struct intel_connector *connector)  { @@ -2005,6
> +2020,8 @@ static int _intel_hdcp2_enable(struct intel_atomic_state *state,
>  		    connector->base.base.id, connector->base.name,
>  		    hdcp->content_type);
> 
> +	intel_hdcp_disable_hdcp_line_rekeying(connector->encoder, hdcp);
> +

>  	ret = hdcp2_authenticate_and_encrypt(state, connector);
>  	if (ret) {
>  		drm_dbg_kms(&i915->drm, "HDCP2 Type%d  Enabling Failed.
> (%d)\n", diff --git a/drivers/gpu/drm/i915/i915_reg.h
> b/drivers/gpu/drm/i915/i915_reg.h index 3f34efcd7d6c..fbf4623cd536 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5630,6 +5630,7 @@ enum skl_power_gate {
>  #define  TRANS_DDI_EDP_INPUT_B_ONOFF	(5 << 12)
>  #define  TRANS_DDI_EDP_INPUT_C_ONOFF	(6 << 12)
>  #define  TRANS_DDI_EDP_INPUT_D_ONOFF	(7 << 12)
> +#define  TRANS_DDI_HDCP_LINE_REKEY_DISABLE	REG_BIT(12)
>  #define  TRANS_DDI_MST_TRANSPORT_SELECT_MASK	REG_GENMASK(11,
> 10)
>  #define  TRANS_DDI_MST_TRANSPORT_SELECT(trans)	\
>  	REG_FIELD_PREP(TRANS_DDI_MST_TRANSPORT_SELECT_MASK,
> trans)
> --
> 2.43.2