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authorHans Verkuil <hans.verkuil@cisco.com>2018-10-04 03:28:21 -0400
committerMauro Carvalho Chehab <mchehab+samsung@kernel.org>2018-10-05 11:22:39 -0400
commit7ec2b3b941a666a942859684281b5f6460a0c234 (patch)
tree7b0f7908bcf07674b3aec8390e03a22e77ea2edc /Documentation/media
parent81e33279d154599db64d608b2a1db619f3b56ce1 (diff)
downloadlinux-7ec2b3b941a666a942859684281b5f6460a0c234.tar.bz2
media: cec: add new tx/rx status bits to detect aborts/timeouts
If the HDMI cable is disconnected or the CEC adapter is manually unconfigured, then all pending transmits and wait-for-replies are aborted. Signal this with new status bits (CEC_RX/TX_STATUS_ABORTED). If due to (usually) a driver bug a transmit never ends (i.e. the transmit_done was never called by the driver), then when this times out the message is marked with CEC_TX_STATUS_TIMEOUT. This should not happen and is an indication of a driver bug. Without a separate status bit for this it was impossible to detect this from userspace. The 'transmit timed out' kernel message is now a warning, so this should be more prominent in the kernel log as well. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.18 and up Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation/media')
-rw-r--r--Documentation/media/uapi/cec/cec-ioc-receive.rst25
1 files changed, 23 insertions, 2 deletions
diff --git a/Documentation/media/uapi/cec/cec-ioc-receive.rst b/Documentation/media/uapi/cec/cec-ioc-receive.rst
index e964074cd15b..b25e48afaa08 100644
--- a/Documentation/media/uapi/cec/cec-ioc-receive.rst
+++ b/Documentation/media/uapi/cec/cec-ioc-receive.rst
@@ -16,10 +16,10 @@ CEC_RECEIVE, CEC_TRANSMIT - Receive or transmit a CEC message
Synopsis
========
-.. c:function:: int ioctl( int fd, CEC_RECEIVE, struct cec_msg *argp )
+.. c:function:: int ioctl( int fd, CEC_RECEIVE, struct cec_msg \*argp )
:name: CEC_RECEIVE
-.. c:function:: int ioctl( int fd, CEC_TRANSMIT, struct cec_msg *argp )
+.. c:function:: int ioctl( int fd, CEC_TRANSMIT, struct cec_msg \*argp )
:name: CEC_TRANSMIT
Arguments
@@ -272,6 +272,19 @@ View On' messages from initiator 0xf ('Unregistered') to destination 0 ('TV').
- The transmit failed after one or more retries. This status bit is
mutually exclusive with :ref:`CEC_TX_STATUS_OK <CEC-TX-STATUS-OK>`.
Other bits can still be set to explain which failures were seen.
+ * .. _`CEC-TX-STATUS-ABORTED`:
+
+ - ``CEC_TX_STATUS_ABORTED``
+ - 0x40
+ - The transmit was aborted due to an HDMI disconnect, or the adapter
+ was unconfigured, or a transmit was interrupted, or the driver
+ returned an error when attempting to start a transmit.
+ * .. _`CEC-TX-STATUS-TIMEOUT`:
+
+ - ``CEC_TX_STATUS_TIMEOUT``
+ - 0x80
+ - The transmit timed out. This should not normally happen and this
+ indicates a driver problem.
.. tabularcolumns:: |p{5.6cm}|p{0.9cm}|p{11.0cm}|
@@ -300,6 +313,14 @@ View On' messages from initiator 0xf ('Unregistered') to destination 0 ('TV').
- The message was received successfully but the reply was
``CEC_MSG_FEATURE_ABORT``. This status is only set if this message
was the reply to an earlier transmitted message.
+ * .. _`CEC-RX-STATUS-ABORTED`:
+
+ - ``CEC_RX_STATUS_ABORTED``
+ - 0x08
+ - The wait for a reply to an earlier transmitted message was aborted
+ because the HDMI cable was disconnected, the adapter was unconfigured
+ or the :ref:`CEC_TRANSMIT <CEC_RECEIVE>` that waited for a
+ reply was interrupted.