From f5580d8d6fd07a569e468fca51f435aa5b122fc4 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Tue, 1 Nov 2016 11:07:17 -0200 Subject: [PATCH] [media] cec: accept two replies for CEC_MSG_INITIATE_ARC The CEC_MSG_INITIATE_ARC message is special since it is the ONLY CEC message that accepts two possible valid replies: CEC_MSG_REPORT_ARC_INITIATED and CEC_MSG_REPORT_ARC_TERMINATED. So if the transmitted message is CEC_MSG_INITIATE_ARC and the remote side replied with CEC_MSG_REPORT_ARC_INITIATED or CEC_MSG_REPORT_ARC_TERMINATED, then a msg->reply value of CEC_MSG_REPORT_ARC_INITIATED or CEC_MSG_REPORT_ARC_TERMINATED will match either reply. I thought about either adding a second reply2 field, but that's ugly for all other messages that have only one reply, and what if in the future a new message is added that can have three replies? Another option would be to add a cec_msg flag, but really, the combination of CEC_MSG_REPORT_ARC_INITIATED and a reply value of one of the two possible replies already functions as a flag. Another advantage of this approach is that it is safe to re-use a cec_msg struct. No need to zero a flags field or a reply2 field. So since this really is an exception in the CEC specification, I decided to implement it as an exception as well. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/media/uapi/cec/cec-ioc-receive.rst | 8 ++++++++ drivers/staging/media/cec/TODO | 15 +-------------- drivers/staging/media/cec/cec-adap.c | 12 ++++++++++++ 3 files changed, 21 insertions(+), 14 deletions(-) diff --git a/Documentation/media/uapi/cec/cec-ioc-receive.rst b/Documentation/media/uapi/cec/cec-ioc-receive.rst index b4dffd2f7dfa..bdf015b1d1dc 100644 --- a/Documentation/media/uapi/cec/cec-ioc-receive.rst +++ b/Documentation/media/uapi/cec/cec-ioc-receive.rst @@ -142,6 +142,14 @@ result. Feature Abort reply. In this case ``rx_status`` will either be set to :ref:`CEC_RX_STATUS_TIMEOUT ` or :ref:`CEC_RX_STATUS_FEATURE_ABORT `. + + If the transmitter message is ``CEC_MSG_INITIATE_ARC`` then the ``reply`` + values ``CEC_MSG_REPORT_ARC_INITIATED`` and ``CEC_MSG_REPORT_ARC_TERMINATED`` + are processed differently: either value will match both possible replies. + The reason is that the ``CEC_MSG_INITIATE_ARC`` message is the only CEC + message that has two possible replies other than Feature Abort. The + ``reply`` field will be updated with the actual reply so that it is + synchronized with the contents of the received message. * - __u8 - ``rx_status`` - The status bits of the received message. See diff --git a/drivers/staging/media/cec/TODO b/drivers/staging/media/cec/TODO index ce69001b0428..5a4cfdf8d15e 100644 --- a/drivers/staging/media/cec/TODO +++ b/drivers/staging/media/cec/TODO @@ -1,18 +1,5 @@ -The reason why cec.c is still in staging is that I would like -to have a bit more confidence in the uABI. The kABI is fine, -no problem there, but I would like to let the public API mature -a bit. +TODOs: -Once I'm confident that I didn't miss anything then the cec.c source -can move to drivers/media and the linux/cec.h and linux/cec-funcs.h -headers can move to uapi/linux and added to uapi/linux/Kbuild to make -them public. - -Hopefully this will happen later in 2016. - -Other TODOs: - -- There are two possible replies to CEC_MSG_INITIATE_ARC. How to handle that? - Should CEC_LOG_ADDR_TYPE_SPECIFIC be replaced by TYPE_2ND_TV and TYPE_PROCESSOR? And also TYPE_SWITCH and TYPE_CDC_ONLY in addition to the TYPE_UNREGISTERED? This should give the framework more information about the device type diff --git a/drivers/staging/media/cec/cec-adap.c b/drivers/staging/media/cec/cec-adap.c index 93b53e602e48..a65d8667b78e 100644 --- a/drivers/staging/media/cec/cec-adap.c +++ b/drivers/staging/media/cec/cec-adap.c @@ -958,6 +958,18 @@ void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg) list_for_each_entry(data, &adap->wait_queue, list) { struct cec_msg *dst = &data->msg; + /* + * The *only* CEC message that has two possible replies + * is CEC_MSG_INITIATE_ARC. + * In this case allow either of the two replies. + */ + if (!abort && dst->msg[1] == CEC_MSG_INITIATE_ARC && + (cmd == CEC_MSG_REPORT_ARC_INITIATED || + cmd == CEC_MSG_REPORT_ARC_TERMINATED) && + (dst->reply == CEC_MSG_REPORT_ARC_INITIATED || + dst->reply == CEC_MSG_REPORT_ARC_TERMINATED)) + dst->reply = cmd; + /* Does the command match? */ if ((abort && cmd != dst->msg[1]) || (!abort && cmd != dst->reply)) -- 2.39.5