From: Ramalingam C <ramalingam.c@intel.com>
To: intel-gfx@lists.freedesktop.org, seanpaul@chromium.org
Cc: daniel.vetter@ffwll.ch, rodrigo.vivi@intel.com
Subject: [PATCH v2 2/8] drm/i915: Stop encryption for repeater with no sink
Date: Sat, 3 Feb 2018 01:41:30 +0530 [thread overview]
Message-ID: <1517602296-2386-3-git-send-email-ramalingam.c@intel.com> (raw)
In-Reply-To: <1517602296-2386-1-git-send-email-ramalingam.c@intel.com>
If a HDCP repeater is detected with zero downstream devices,
HDCP spec approves either of below actions:
1. Dont continue on second stage authentication. Disable encryption.
2. Continue with second stage authentication excluding the KSV list and
on success, continue encryption.
Since disable encryption is agreed, repeater is not expected to have its
own display. So there is no consumption of the display content in such
setup.
Hence, incase of repeater with zero device count, this patch fails the
HDCP authentication and stops the HDCP encryption.
v2:
Rephrased commit msg and added comments in code [Seanpaul]
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
---
drivers/gpu/drm/i915/intel_hdcp.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index de9a925c122d..0a1ef82c77a2 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -166,10 +166,16 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,
return -EPERM;
}
- /* If there are no downstream devices, we're all done. */
+ /*
+ * When repeater reports 0 device count, HDCP1.4 spec allows disabling
+ * the HDCP encryption. That implies that repeater can't have its own
+ * display. As there is no consumption of encrypted content in the
+ * repeater with 0 downstream devices, we are failing the
+ * authentication.
+ */
num_downstream = DRM_HDCP_NUM_DOWNSTREAM(bstatus[0]);
if (num_downstream == 0)
- return 0;
+ return -EINVAL;
ksv_fifo = kzalloc(num_downstream * DRM_HDCP_KSV_LEN, GFP_KERNEL);
if (!ksv_fifo)
--
2.7.4
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next prev parent reply other threads:[~2018-02-02 20:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-02 20:11 [PATCH v2 0/8] Adhering to HDCP1.4 Compliance Test Spec Ramalingam C
2018-02-02 20:11 ` [PATCH v2 1/8] drm/i915: Handle failure from 2nd stage HDCP auth Ramalingam C
2018-02-02 20:52 ` Sean Paul
2018-02-02 20:11 ` Ramalingam C [this message]
2018-02-02 20:52 ` [PATCH v2 2/8] drm/i915: Stop encryption for repeater with no sink Sean Paul
2018-02-02 20:11 ` [PATCH v2 3/8] drm/i915: Connector info in HDCP debug msgs Ramalingam C
2018-02-02 20:52 ` Sean Paul
2018-02-02 20:11 ` [PATCH v2 4/8] drm/i915: Retry HDCP bksv read Ramalingam C
2018-02-02 20:44 ` Sean Paul
2018-02-02 20:11 ` [PATCH v2 5/8] drm/i915: Optimize HDCP key load Ramalingam C
2018-02-02 20:11 ` [PATCH v2 6/8] drm/i915: Detect panel's hdcp capability Ramalingam C
2018-02-02 20:46 ` Sean Paul
2018-02-02 20:11 ` [PATCH v2 7/8] drm/i915: Reauthenticate HDCP on failure Ramalingam C
2018-02-02 20:51 ` Sean Paul
2018-02-02 20:11 ` [PATCH v2 8/8] drm/i915: fix misalignment in HDCP register def Ramalingam C
2018-02-02 21:20 ` ✗ Fi.CI.BAT: warning for Adhering to HDCP1.4 Compliance Test Spec (rev2) Patchwork
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