[PATCHv2 6/7] cec: allow any initiator for Ping and Image/Text View On

[Hans Verkuil <hverkuil-cisco@xs4all.nl>]

Some displays pull down the HPD when in standby, but CEC is still
active and the display can be woken up by sending an Image View On
or Text View On CEC command. The CEC specification doesn't tell you
what the initiator should be for such a command (without a HPD it's
unclear if the CEC adapter can claim a logical address).

This patch allows any initiator value when there is no HPD for the
Image/Text View On commands and for the Ping command.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/cec/cec-adap.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index 9a1ec9299aca..5827d8c3742a 100644
--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -809,14 +809,23 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
 				__func__);
 			return -EINVAL;
 		}
-		if (msg->len > 1 && adap->is_configured &&
+		if (adap->is_configured &&
 		    !cec_has_log_addr(adap, cec_msg_initiator(msg))) {
 			dprintk(1, "%s: initiator has unknown logical address %d\n",
 				__func__, cec_msg_initiator(msg));
 			return -EINVAL;
 		}
+		/*
+		 * Special case: allow Ping and IMAGE/TEXT_VIEW_ON to be
+		 * transmitted to a TV, even if the adapter is unconfigured.
+		 * This makes it possible to detect or wake up displays that
+		 * pull down the HPD when in standby.
+		 */
 		if (!adap->is_configured && !adap->is_configuring &&
-		    msg->msg[0] != 0xf0) {
+		    (msg->len > 2 ||
+		     cec_msg_destination(msg) != CEC_LOG_ADDR_TV ||
+		     (msg->len == 2 && msg->msg[1] != CEC_MSG_IMAGE_VIEW_ON &&
+		      msg->msg[1] != CEC_MSG_TEXT_VIEW_ON))) {
 			dprintk(1, "%s: adapter is unconfigured\n", __func__);
 			return -ENONET;
 		}
-- 
2.20.1