drm/i915: Check for downstream topology errors (49d85d03) · Commits · 戴 / test

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:

Ramalingam C <ramalingam.c@intel.com> [seanpaul fixed checkpatch alignment issue] Signed-off-by:

Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/1516254488-4971-5-git-send-email-ramalingam.c@intel.com

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

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