> -----Original Message-----
> From: Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>
> Sent: Tuesday, October 29, 2024 2:23 PM
> To: intel-xe@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: Borah, Chaitanya Kumar <chaitanya.kumar.borah@xxxxxxxxx>; Kandpal,
> Suraj <suraj.kandpal@xxxxxxxxx>
> Subject: [PATCH] drm/i915/hdcp: Add the loop only for DP encoders
>
> Add the loop on the first read and write only for DP/DPMST encoders as this
> issue is only observed here no need to burden other encoders with extra
> retries.
It would make the motivation of the patch clearer if we describe "this issue" here.
>
> Fixes: 9d5a05f86d2f ("drm/i915/hdcp: Retry first read and writes to
> downstream")
> Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_hdcp.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c
> b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index ed6aa87403e2..fcfb5a9f303a 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -1503,6 +1503,8 @@ static int hdcp2_deauthenticate_port(struct
> intel_connector *connector) static int
> hdcp2_authentication_key_exchange(struct intel_connector *connector) {
> struct intel_display *display = to_intel_display(connector);
> + struct intel_digital_port *dig_port =
> + intel_attached_dig_port(connector);
> struct intel_hdcp *hdcp = &connector->hdcp;
> union {
> struct hdcp2_ake_init ake_init;
> @@ -1513,12 +1515,18 @@ static int
> hdcp2_authentication_key_exchange(struct intel_connector *connector)
> } msgs;
> const struct intel_hdcp_shim *shim = hdcp->shim;
> size_t size;
> - int ret, i;
> + int ret, i, max_retries;
>
> /* Init for seq_num */
> hdcp->seq_num_v = 0;
> hdcp->seq_num_m = 0;
>
> + if (intel_encoder_is_dp(&dig_port->base) ||
> + intel_encoder_is_mst(&dig_port->base))
> + max_retries = 10;
> + else
> + max_retries = 1;
> +
> ret = hdcp2_prepare_ake_init(connector, &msgs.ake_init);
> if (ret < 0)
> return ret;
> @@ -1536,7 +1544,7 @@ static int
> hdcp2_authentication_key_exchange(struct intel_connector *connector)
> * authentication. The values of 10 and delay of 50ms was decided
> based
> * on multiple trial and errors.
> */
Perhaps this comment can use an update too.
Functionally LGTM.
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@xxxxxxxxx>
> - for (i = 0; i < 10; i++) {
> + for (i = 0; i < max_retries; i++) {
> if (!intel_hdcp2_get_capability(connector)) {
> msleep(50);
> continue;
> --
> 2.34.1
