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authorHans Verkuil <hans.verkuil@cisco.com>2016-11-21 13:15:45 -0200
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2016-11-22 05:43:07 -0200
commit3f98da9636029486b86eb63f0b57b91dcbd880b0 (patch)
treeae45d8ad944a54e94dd8fd1990c120f8e81fd56d /drivers/media/cec/cec-adap.c
parent7febb418a32a2caaef57bca91df41c658406670d (diff)
downloadop-kernel-dev-3f98da9636029486b86eb63f0b57b91dcbd880b0.zip
op-kernel-dev-3f98da9636029486b86eb63f0b57b91dcbd880b0.tar.gz
[media] cec: ignore messages that we initiated
Some CEC adapters will receive messages that they initiated. Add a check that will ignore such messages. Most hardware behaves correctly in this respect, but I have seen adapters that don't, so just filter this out in the framework. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'drivers/media/cec/cec-adap.c')
-rw-r--r--drivers/media/cec/cec-adap.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index d9c6f2c..0ea4efb 100644
--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -869,6 +869,21 @@ void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg)
if (WARN_ON(!msg->len || msg->len > CEC_MAX_MSG_SIZE))
return;
+ /*
+ * Some CEC adapters will receive the messages that they transmitted.
+ * This test filters out those messages by checking if we are the
+ * initiator, and just returning in that case.
+ *
+ * Note that this won't work if this is an Unregistered device.
+ *
+ * It is bad practice if the hardware receives the message that it
+ * transmitted and luckily most CEC adapters behave correctly in this
+ * respect.
+ */
+ if (msg_init != CEC_LOG_ADDR_UNREGISTERED &&
+ cec_has_log_addr(adap, msg_init))
+ return;
+
msg->rx_ts = ktime_get_ns();
msg->rx_status = CEC_RX_STATUS_OK;
msg->sequence = msg->reply = msg->timeout = 0;
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