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| author |   Hans Verkuil <hans.verkuil@cisco.com> | 2018-10-04 03:28:21 -0400 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2018-10-05 11:22:39 -0400 |
| commit | 7ec2b3b941a666a942859684281b5f6460a0c234 (patch) | |
| tree | 7b0f7908bcf07674b3aec8390e03a22e77ea2edc /Documentation/media | |
| parent | media: cec-core.rst: improve cec_transmit_done documentation (diff) | |
| download | linux-dev-7ec2b3b941a666a942859684281b5f6460a0c234.tar.xz linux-dev-7ec2b3b941a666a942859684281b5f6460a0c234.zip | |
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.rst | 25 |
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. |