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author | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2022-03-03 14:01:44 +0000 |
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committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2022-04-24 07:38:19 +0100 |
commit | 590a8e564c6eff7e77a84e728612f1269e3c0685 (patch) | |
tree | a4364838c77cbcb7a9d5957a4f79a313d192a78d /drivers/media/cec | |
parent | 3813c932ed970dd4f413498ccecb03c73c4f1784 (diff) | |
download | lwn-590a8e564c6eff7e77a84e728612f1269e3c0685.tar.gz lwn-590a8e564c6eff7e77a84e728612f1269e3c0685.zip |
media: cec: abort if the current transmit was canceled
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>
Diffstat (limited to 'drivers/media/cec')
-rw-r--r-- | drivers/media/cec/core/cec-adap.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/media/cec/core/cec-adap.c b/drivers/media/cec/core/cec-adap.c index 1a095308f3ab..b7ca429604ed 100644 --- a/drivers/media/cec/core/cec-adap.c +++ b/drivers/media/cec/core/cec-adap.c @@ -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); } |