Commit 85f720f7 authored by Dave Airlie's avatar Dave Airlie
Browse files

Merge tag 'drm-intel-next-fixes-2024-11-21' of... 

Merge tag 'drm-intel-next-fixes-2024-11-21' of https://gitlab.freedesktop.org/drm/i915/kernel

 into drm-next

- Fix when the first read and write are retried [hdcp] (Suraj Kandpal)

Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
From: Tvrtko Ursulin <tursulin@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/Zz7xWbodMn9zZD_C@linux
parents a163b895 376a33c4

drivers/gpu/drm/i915/display/intel_hdcp.c

+20 −12
Original line number Diff line number Diff line
@@ -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;
@@ -1513,30 +1515,36 @@ 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;



	/*

	 * Retry the first read and write to downstream at least 10 times

	 * with a 50ms delay if not hdcp2 capable(dock decides to stop advertising

	 * hdcp2 capability for some reason). The reason being that

	 * during suspend resume dock usually keeps the HDCP2 registers inaccesible

	 * causing AUX error. This wouldn't be a big problem if the userspace

	 * just kept retrying with some delay while it continues to play low

	 * value content but most userpace applications end up throwing an error

	 * when it receives one from KMD. This makes sure we give the dock

	 * and the sink devices to complete its power cycle and then try HDCP

	 * authentication. The values of 10 and delay of 50ms was decided based

	 * on multiple trial and errors.

	 * with a 50ms delay if not hdcp2 capable for DP/DPMST encoders

	 * (dock decides to stop advertising hdcp2 capability for some reason).

	 * The reason being that during suspend resume dock usually keeps the

	 * HDCP2 registers inaccesible causing AUX error. This wouldn't be a

	 * big problem if the userspace just kept retrying with some delay while

	 * it continues to play low value content but most userpace applications

	 * end up throwing an error when it receives one from KMD. This makes

	 * sure we give the dock and the sink devices to complete its power cycle

	 * and then try HDCP authentication. The values of 10 and delay of 50ms

	 * was decided based on multiple trial and errors.

	 */

	for (i = 0; i < 10; i++) {

	for (i = 0; i < max_retries; i++) {

		if (!intel_hdcp2_get_capability(connector)) {

			msleep(50);

			continue;