[PATCH 08/19] drm/i915/dp: Factor out intel_dp_read_dprx_caps()

[Shankar, Uma]

> -----Original Message-----
> From: dri-devel <dri-devel-bounces at lists.freedesktop.org> On Behalf Of Imre
> Deak
> Sent: Tuesday, January 23, 2024 3:59 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org
> Subject: [PATCH 08/19] drm/i915/dp: Factor out intel_dp_read_dprx_caps()
> 
> Factor out a function to read the sink's DPRX capabilities used by a follow-up
> patch enabling the DP tunnel BW allocation mode.

Looks good to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  .../drm/i915/display/intel_dp_link_training.c | 30 +++++++++++++++----
> .../drm/i915/display/intel_dp_link_training.h |  1 +
>  2 files changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index 7b140cbf8dd31..fb84ca98bb7ab 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -162,6 +162,28 @@ static int intel_dp_init_lttpr(struct intel_dp *intel_dp,
> const u8 dpcd[DP_RECEI
>  	return lttpr_count;
>  }
> 
> +int intel_dp_read_dprx_caps(struct intel_dp *intel_dp, u8
> +dpcd[DP_RECEIVER_CAP_SIZE]) {
> +	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +
> +	if (intel_dp_is_edp(intel_dp))
> +		return 0;
> +
> +	/*
> +	 * Detecting LTTPRs must be avoided on platforms with an AUX timeout
> +	 * period < 3.2ms. (see DP Standard v2.0, 2.11.2, 3.6.6.1).
> +	 */
> +	if (DISPLAY_VER(i915) >= 10 && !IS_GEMINILAKE(i915))
> +		if (drm_dp_dpcd_probe(&intel_dp->aux,
> +
> DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV))
> +			return -EIO;
> +
> +	if (drm_dp_read_dpcd_caps(&intel_dp->aux, dpcd))
> +		return -EIO;
> +
> +	return 0;
> +}
> +
>  /**
>   * intel_dp_init_lttpr_and_dprx_caps - detect LTTPR and DPRX caps, init the
> LTTPR link training mode
>   * @intel_dp: Intel DP struct
> @@ -192,12 +214,10 @@ int intel_dp_init_lttpr_and_dprx_caps(struct intel_dp
> *intel_dp)
>  	if (!intel_dp_is_edp(intel_dp) &&
>  	    (DISPLAY_VER(i915) >= 10 && !IS_GEMINILAKE(i915))) {
>  		u8 dpcd[DP_RECEIVER_CAP_SIZE];
> +		int err = intel_dp_read_dprx_caps(intel_dp, dpcd);
> 
> -		if (drm_dp_dpcd_probe(&intel_dp->aux,
> DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV))
> -			return -EIO;
> -
> -		if (drm_dp_read_dpcd_caps(&intel_dp->aux, dpcd))
> -			return -EIO;
> +		if (err != 0)
> +			return err;
> 
>  		lttpr_count = intel_dp_init_lttpr(intel_dp, dpcd);
>  	}
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> index 2c8f2775891b0..19836a8a4f904 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> @@ -11,6 +11,7 @@
>  struct intel_crtc_state;
>  struct intel_dp;
> 
> +int intel_dp_read_dprx_caps(struct intel_dp *intel_dp, u8
> +dpcd[DP_RECEIVER_CAP_SIZE]);
>  int intel_dp_init_lttpr_and_dprx_caps(struct intel_dp *intel_dp);
> 
>  void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
> --
> 2.39.2