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Commit 49d85d03 authored by Ramalingam C's avatar Ramalingam C Committed by Sean Paul
Browse files

drm/i915: Check for downstream topology errors 



HDCP compliant Repeaters can support max of 127 devices and max
depth of 7 for downstream topology.

If these max limits are exceeded, repeater will set the
topology error flags MAX_CASCADE_EXCEEDED and/or MAX_DEVS_EXCEEDED
in Bstatus followed by asserting READY/CP_IRQ for HDCP transmitter.

This patch check for these error flags as soon as READY bit is asserted.

Signed-off-by: default avatarRamalingam C <ramalingam.c@intel.com>
[seanpaul fixed checkpatch alignment issue]
Signed-off-by: default avatarSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1516254488-4971-5-git-send-email-ramalingam.c@intel.com
parent 24b42cba

drivers/gpu/drm/i915/intel_hdcp.c

+6 −0
Original line number Diff line number Diff line
@@ -160,6 +160,12 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port, 
	if (ret)

		return ret;



	if (DRM_HDCP_MAX_DEVICE_EXCEEDED(bstatus[0]) ||

	    DRM_HDCP_MAX_CASCADE_EXCEEDED(bstatus[1])) {

		DRM_ERROR("Max Topology Limit Exceeded\n");

		return -EPERM;

	}



	/* If there are no downstream devices, we're all done. */

	num_downstream = DRM_HDCP_NUM_DOWNSTREAM(bstatus[0]);

	if (num_downstream == 0) {

include/drm/drm_hdcp.h

+2 −0
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ 
#define DRM_HDCP_V_PRIME_PART_LEN		4

#define DRM_HDCP_V_PRIME_NUM_PARTS		5

#define DRM_HDCP_NUM_DOWNSTREAM(x)		(x & 0x3f)

#define DRM_HDCP_MAX_CASCADE_EXCEEDED(x)	(x & BIT(3))

#define DRM_HDCP_MAX_DEVICE_EXCEEDED(x)		(x & BIT(7))



/* Slave address for the HDCP registers in the receiver */

#define DRM_HDCP_DDC_ADDR			0x3A