[PATCH v4 3/7] drm/i915/xe3lpd: Disable HDCP Line Rekeying for Xe3

[Matt Roper]

On Fri, Oct 18, 2024 at 01:03:07PM -0700, Matt Atwood wrote:
> From: Suraj Kandpal <suraj.kandpal at intel.com>
> 
> We need to disable HDCP Line Rekeying for Xe3 when we are using an HDMI
> encoder.

This is still missing the "why" for this change.  Is there a bspec
reference that gives the details?  From the description of the bit
itself, it sounds like the setting here (for both Xe3 and earlier Xe2)
should be based on the HDCP version rather than the platform/stepping.

As mentioned previously, this entire function is labeled as "/* WA:
16022217614 */"  If we're now using this function for something other
than that specific workaround, then we need to fix/move that comment.


Matt

> 
> v2: add additional definition instead of function, commit message typo
> fix and update.
> v3: restore lost conditional from v2.
> v4: subject line and subject message updated, fix the if ladder order,
> fix the bit definition order.
> 
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> Signed-off-by: Matt Atwood <matthew.s.atwood at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hdcp.c | 10 +++++++---
>  drivers/gpu/drm/i915/i915_reg.h           |  1 +
>  2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index ed6aa87403e2..70dfc9d4d6ac 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -43,14 +43,18 @@ intel_hdcp_disable_hdcp_line_rekeying(struct intel_encoder *encoder,
>  		return;
>  
>  	if (DISPLAY_VER(display) >= 14) {
> -		if (IS_DISPLAY_VER_STEP(display, IP_VER(14, 0), STEP_D0, STEP_FOREVER))
> -			intel_de_rmw(display, MTL_CHICKEN_TRANS(hdcp->cpu_transcoder),
> -				     0, HDCP_LINE_REKEY_DISABLE);
> +		if (DISPLAY_VER(display) >= 30)
> +			intel_de_rmw(display,
> +				     TRANS_DDI_FUNC_CTL(display, hdcp->cpu_transcoder),
> +				     0, XE3_TRANS_DDI_HDCP_LINE_REKEY_DISABLE);
>  		else if (IS_DISPLAY_VER_STEP(display, IP_VER(14, 1), STEP_B0, STEP_FOREVER) ||
>  			 IS_DISPLAY_VER_STEP(display, IP_VER(20, 0), STEP_B0, STEP_FOREVER))
>  			intel_de_rmw(display,
>  				     TRANS_DDI_FUNC_CTL(display, hdcp->cpu_transcoder),
>  				     0, TRANS_DDI_HDCP_LINE_REKEY_DISABLE);
> +		else if (IS_DISPLAY_VER_STEP(display, IP_VER(14, 0), STEP_D0, STEP_FOREVER))
> +			intel_de_rmw(display, MTL_CHICKEN_TRANS(hdcp->cpu_transcoder),
> +				     0, HDCP_LINE_REKEY_DISABLE);
>  	}
>  }
>  
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 89e4381f8baa..8d758947f301 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3817,6 +3817,7 @@ enum skl_power_gate {
>  #define  TRANS_DDI_PVSYNC		(1 << 17)
>  #define  TRANS_DDI_PHSYNC		(1 << 16)
>  #define  TRANS_DDI_PORT_SYNC_ENABLE	REG_BIT(15)
> +#define  XE3_TRANS_DDI_HDCP_LINE_REKEY_DISABLE	REG_BIT(15)
>  #define  TRANS_DDI_EDP_INPUT_MASK	(7 << 12)
>  #define  TRANS_DDI_EDP_INPUT_A_ON	(0 << 12)
>  #define  TRANS_DDI_EDP_INPUT_A_ONOFF	(4 << 12)
> -- 
> 2.45.0
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation