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media: cec: add new tx/rx status bits to detect aborts/timeouts

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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>
This commit is contained in:
Hans Verkuil 2018-10-04 03:28:21 -04:00 committed by Mauro Carvalho Chehab
parent 81e33279d1
commit 7ec2b3b941
3 changed files with 44 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
Documentation/media/uapi/cec/cec-ioc-receive.rst
View File

@ -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.

66
drivers/media/cec/cec-adap.c
View File

@ -354,7 +354,7 @@ static void cec_data_completed(struct cec_data *data)
*
* This function is called with adap->lock held.
*/
static void cec_data_cancel(struct cec_data *data)
static void cec_data_cancel(struct cec_data *data, u8 tx_status)
{
/*
* It's either the current transmit, or it is a pending
@ -369,13 +369,11 @@ static void cec_data_cancel(struct cec_data *data)
}
if (data->msg.tx_status & CEC_TX_STATUS_OK) {
/* Mark the canceled RX as a timeout */
data->msg.rx_ts = ktime_get_ns();
data->msg.rx_status = CEC_RX_STATUS_TIMEOUT;
data->msg.rx_status = CEC_RX_STATUS_ABORTED;
} else {
/* Mark the canceled TX as an error */
data->msg.tx_ts = ktime_get_ns();
data->msg.tx_status |= CEC_TX_STATUS_ERROR |
data->msg.tx_status |= tx_status |
CEC_TX_STATUS_MAX_RETRIES;
data->msg.tx_error_cnt++;
data->attempts = 0;
@ -403,15 +401,15 @@ static void cec_flush(struct cec_adapter *adap)
while (!list_empty(&adap->transmit_queue)) {
data = list_first_entry(&adap->transmit_queue,
struct cec_data, list);
cec_data_cancel(data);
cec_data_cancel(data, CEC_TX_STATUS_ABORTED);
}
if (adap->transmitting)
cec_data_cancel(adap->transmitting);
cec_data_cancel(adap->transmitting, CEC_TX_STATUS_ABORTED);
/* Cancel the pending timeout work. */
list_for_each_entry_safe(data, n, &adap->wait_queue, list) {
if (cancel_delayed_work(&data->work))
cec_data_cancel(data);
cec_data_cancel(data, CEC_TX_STATUS_OK);
/*
* If cancel_delayed_work returned false, then
* the cec_wait_timeout function is running,
@ -487,12 +485,13 @@ int cec_thread_func(void *_adap)
* so much traffic on the bus that the adapter was
* unable to transmit for CEC_XFER_TIMEOUT_MS (2.1s).
*/
dprintk(1, "%s: message %*ph timed out\n", __func__,
pr_warn("cec-%s: message %*ph timed out\n", adap->name,
adap->transmitting->msg.len,
adap->transmitting->msg.msg);
adap->tx_timeouts++;
/* Just give up on this. */
cec_data_cancel(adap->transmitting);
cec_data_cancel(adap->transmitting,
CEC_TX_STATUS_TIMEOUT);
goto unlock;
}
@ -543,7 +542,7 @@ int cec_thread_func(void *_adap)
/* Tell the adapter to transmit, cancel on error */
if (adap->ops->adap_transmit(adap, data->attempts,
signal_free_time, &data->msg))
cec_data_cancel(data);
cec_data_cancel(data, CEC_TX_STATUS_ABORTED);
unlock:
mutex_unlock(&adap->lock);
@ -715,8 +714,6 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
{
struct cec_data *data;
u8 last_initiator = 0xff;
unsigned int timeout;
int res = 0;
msg->rx_ts = 0;
msg->tx_ts = 0;
@ -858,48 +855,21 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
if (!block)
return 0;
/*
* If we don't get a completion before this time something is really
* wrong and we time out.
*/
timeout = CEC_XFER_TIMEOUT_MS;
/* Add the requested timeout if we have to wait for a reply as well */
if (msg->timeout)
timeout += msg->timeout;
/*
* Release the lock and wait, retake the lock afterwards.
*/
mutex_unlock(&adap->lock);
res = wait_for_completion_killable_timeout(&data->c,
msecs_to_jiffies(timeout));
wait_for_completion_killable(&data->c);
mutex_lock(&adap->lock);
if (data->completed) {
/* The transmit completed (possibly with an error) */
*msg = data->msg;
kfree(data);
return 0;
}
/*
* The wait for completion timed out or was interrupted, so mark this
* as non-blocking and disconnect from the filehandle since it is
* still 'in flight'. When it finally completes it will just drop the
* result silently.
*/
data->blocking = false;
if (data->fh)
list_del(&data->xfer_list);
data->fh = NULL;
/* Cancel the transmit if it was interrupted */
if (!data->completed)
cec_data_cancel(data, CEC_TX_STATUS_ABORTED);
if (res == 0) { /* timed out */
/* Check if the reply or the transmit failed */
if (msg->timeout && (msg->tx_status & CEC_TX_STATUS_OK))
msg->rx_status = CEC_RX_STATUS_TIMEOUT;
else
msg->tx_status = CEC_TX_STATUS_MAX_RETRIES;
}
return res > 0 ? 0 : res;
/* The transmit completed (possibly with an error) */
*msg = data->msg;
kfree(data);
return 0;
}
/* Helper function to be used by drivers and this framework. */

3
include/uapi/linux/cec.h
View File

@ -152,10 +152,13 @@ static inline void cec_msg_set_reply_to(struct cec_msg *msg,
#define CEC_TX_STATUS_LOW_DRIVE (1 << 3)
#define CEC_TX_STATUS_ERROR (1 << 4)
#define CEC_TX_STATUS_MAX_RETRIES (1 << 5)
#define CEC_TX_STATUS_ABORTED (1 << 6)
#define CEC_TX_STATUS_TIMEOUT (1 << 7)
#define CEC_RX_STATUS_OK (1 << 0)
#define CEC_RX_STATUS_TIMEOUT (1 << 1)
#define CEC_RX_STATUS_FEATURE_ABORT (1 << 2)
#define CEC_RX_STATUS_ABORTED (1 << 3)
static inline int cec_msg_status_is_ok(const struct cec_msg *msg)
{