[Intel-gfx] [PATCH RESEND 4/7] drm/i915/mst: abstract handling of link status in DP MST

[Shankar, Uma]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Jani Nikula
> Sent: Wednesday, January 12, 2022 4:33 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Nikula, Jani <jani.nikula at intel.com>
> Subject: [Intel-gfx] [PATCH RESEND 4/7] drm/i915/mst: abstract handling of link
> status in DP MST
> 
> We'll want to expand on this, so abstract it to a separate function first. Improve
> debug logging while at it.

Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 6de39056e2f8..5a7976768b06 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3639,6 +3639,21 @@ intel_dp_mst_hpd_irq(struct intel_dp *intel_dp, u8 *esi,
> bool *handled)
>  	}
>  }
> 
> +static bool intel_dp_mst_link_status(struct intel_dp *intel_dp, u8
> +*esi) {
> +	struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
> +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +
> +	if (!drm_dp_channel_eq_ok(&esi[10], intel_dp->lane_count)) {
> +		drm_dbg_kms(&i915->drm,
> +			    "[ENCODER:%d:%s] channel EQ not ok, retraining\n",
> +			    encoder->base.base.id, encoder->base.name);
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
>  /**
>   * intel_dp_check_mst_status - service any pending MST interrupts, check link status
>   * @intel_dp: Intel DP struct
> @@ -3686,11 +3701,9 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
>  		drm_dbg_kms(&i915->drm, "DPRX ESI: %4ph\n", esi);
> 
>  		/* check link status - esi[10] = 0x200c */
> -		if (intel_dp->active_mst_links > 0 && link_ok &&
> -		    !drm_dp_channel_eq_ok(&esi[10], intel_dp->lane_count)) {
> -			drm_dbg_kms(&i915->drm,
> -				    "channel EQ not ok, retraining\n");
> -			link_ok = false;
> +		if (intel_dp->active_mst_links > 0 && link_ok) {
> +			if (!intel_dp_mst_link_status(intel_dp, esi))
> +				link_ok = false;
>  		}
> 
>  		intel_dp_mst_hpd_irq(intel_dp, esi, &handled);
> --
> 2.30.2