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media: cec: abort if the current transmit was canceled

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If a transmit-in-progress was canceled, then, once the transmit
is done, mark it as aborted and refrain from retrying the transmit.

To signal this situation the new transmit_in_progress_aborted field is
set to true.

The old implementation would just set adap->transmitting to NULL and
set adap->transmit_in_progress to false, but on the hardware level
the transmit was still ongoing. However, the framework would think
the transmit was aborted, and if a new transmit was issued, then
it could overwrite the HW buffer containing the old transmit with the
new transmit, leading to garbled data on the CEC bus.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Hans Verkuil 2022-03-03 14:01:44 +00:00 committed by Mauro Carvalho Chehab
parent 3813c932ed
commit 590a8e564c
2 changed files with 17 additions and 3 deletions
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14
drivers/media/cec/core/cec-adap.c
View File

@ -421,7 +421,7 @@ static void cec_flush(struct cec_adapter *adap)
cec_data_cancel(data, CEC_TX_STATUS_ABORTED);
}
if (adap->transmitting)
cec_data_cancel(adap->transmitting, CEC_TX_STATUS_ABORTED);
adap->transmit_in_progress_aborted = true;
/* Cancel the pending timeout work. */
list_for_each_entry_safe(data, n, &adap->wait_queue, list) {
@ -572,6 +572,7 @@ int cec_thread_func(void *_adap)
if (data->attempts == 0)
data->attempts = attempts;
adap->transmit_in_progress_aborted = false;
/* Tell the adapter to transmit, cancel on error */
if (adap->ops->adap_transmit(adap, data->attempts,
signal_free_time, &data->msg))
@ -599,6 +600,8 @@ void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
struct cec_msg *msg;
unsigned int attempts_made = arb_lost_cnt + nack_cnt +
low_drive_cnt + error_cnt;
bool done = status & (CEC_TX_STATUS_MAX_RETRIES | CEC_TX_STATUS_OK);
bool aborted = adap->transmit_in_progress_aborted;
dprintk(2, "%s: status 0x%02x\n", __func__, status);
if (attempts_made < 1)
@ -619,6 +622,7 @@ void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
goto wake_thread;
}
adap->transmit_in_progress = false;
adap->transmit_in_progress_aborted = false;
msg = &data->msg;
@ -639,8 +643,7 @@ void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
* the hardware didn't signal that it retried itself (by setting
* CEC_TX_STATUS_MAX_RETRIES), then we will retry ourselves.
*/
if (data->attempts > attempts_made &&
!(status & (CEC_TX_STATUS_MAX_RETRIES | CEC_TX_STATUS_OK))) {
if (!aborted && data->attempts > attempts_made && !done) {
/* Retry this message */
data->attempts -= attempts_made;
if (msg->timeout)
@ -655,6 +658,8 @@ void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
goto wake_thread;
}
if (aborted && !done)
status |= CEC_TX_STATUS_ABORTED;
data->attempts = 0;
/* Always set CEC_TX_STATUS_MAX_RETRIES on error */
@ -1596,6 +1601,9 @@ static void cec_activate_cnt_dec(struct cec_adapter *adap)
WARN_ON(adap->ops->adap_enable(adap, false));
adap->last_initiator = 0xff;
adap->transmit_in_progress = false;
adap->transmit_in_progress_aborted = false;
if (adap->transmitting)
cec_data_cancel(adap->transmitting, CEC_TX_STATUS_ABORTED);
mutex_unlock(&adap->devnode.lock);
}

6
include/media/cec.h
View File

@ -163,6 +163,11 @@ struct cec_adap_ops {
* @wait_queue: queue of transmits waiting for a reply
* @transmitting: CEC messages currently being transmitted
* @transmit_in_progress: true if a transmit is in progress
* @transmit_in_progress_aborted: true if a transmit is in progress is to be
* aborted. This happens if the logical address is
* invalidated while the transmit is ongoing. In that
* case the transmit will finish, but will not retransmit
* and be marked as ABORTED.
* @kthread_config: kthread used to configure a CEC adapter
* @config_completion: used to signal completion of the config kthread
* @kthread: main CEC processing thread
@ -218,6 +223,7 @@ struct cec_adapter {
struct list_head wait_queue;
struct cec_data *transmitting;
bool transmit_in_progress;
bool transmit_in_progress_aborted;
struct task_struct *kthread_config;
struct completion config_completion;