[Intel-gfx] [PATCH v2 4/5] drm/i915: dont retry stream management at seq_num_m roll over

[Sean Paul]

On Wed, Feb 12, 2020 at 03:59:41PM +0530, Ramalingam C wrote:
> When roll over detected for seq_num_m, we shouldn't continue with stream
> management with rolled over value.
> 
> So we are terminating the stream management retry, on roll over of the
> seq_num_m.
> 
> v2:
>   using drm_dbg_kms instead of DRM_DEBUG_KMS [Anshuman]
> v3:
>   dev_priv is used as i915 [JaniN]
> 
> Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hdcp.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index b24d12efae0a..b35f50d4a0e9 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -1419,11 +1419,6 @@ int _hdcp2_propagate_stream_management_info(struct intel_connector *connector)
>  
>  err_exit:
>  	hdcp->seq_num_m++;
> -	if (hdcp->seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
> -		DRM_DEBUG_KMS("seq_num_m roll over.\n");
> -		ret = -1;
> -	}
> -
>  	return ret;
>  }
>  
> @@ -1618,8 +1613,11 @@ hdcp2_propagate_stream_management_info(struct intel_connector *connector)
>  
>  	for (i = 0; i < tries; i++) {
>  		ret = _hdcp2_propagate_stream_management_info(connector);
> -		if (!ret)
> +		if (!ret || connector->hdcp.seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
> +			if (connector->hdcp.seq_num_m > HDCP_2_2_SEQ_NUM_MAX)
> +				drm_dbg_kms(&i915->drm, "seq_num_m roll over.\n");
>  			break;
> +		}

IMO it doesn't read quite right bunching up a success outcome and a failure,
and it's actually less code (character-wise) to do:

                if (connector->hdcp.seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
                        drm_dbg_kms(&i915->drm, "seq_num_m roll over.\n");
                        break;
                } else if (!ret) {
                        break;
                }

feel free to add

Reviewed-by: Sean Paul <sean at poorly.run>

with this addressed

>  
>  		drm_dbg_kms(&i915->drm,
>  			    "HDCP2 stream management %d of %d Failed.(%d)\n",
> -- 
> 2.20.1
> 
> _______________________________________________
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> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Sean Paul, Software Engineer, Google / Chromium OS