Re: [PATCH v2 02/12] drm/i915/xe3lpd: Disable HDCP Line Rekeying for Xe3

[Matt Roper <matthew.d.roper@intel.com>]

On Wed, Oct 23, 2024 at 02:46:51PM -0700, Clint Taylor wrote:
> From: Suraj Kandpal <suraj.kandpal@intel.com>
> 
> We need to disable HDCP Line Rekeying for Xe3 when we are using an HDMI
> encoder.
> 
> 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.

Copying over my feedback from the previous version, since I think this
new series was getting posted at the same time I left my comment:

"""
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.
"""

> 
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>

BTW, for all of the patches in this series, you need to add your own
s-o-b line at the bottom as well if it doesn't already exist.


Matt

> ---
>  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)
> -- 
> 2.25.1
> 

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