media: cec: core: count low-drive, error and arb-lost conditions

Count how many Low Drive, Error and Arbitration Lost transmit
status errors occurred, and expose that in debugfs.

Also log the first 8 transmits that result in Low Drive or Error
conditions. That really should not happen with well-behaved CEC devices
and good HDMI cables.

This is useful to detect and debug HDMI cable issues.

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 2023-10-11 10:17:59 +02:00 committed by Mauro Carvalho Chehab
parent bbd267daf4
commit 632b8b044a
2 changed files with 69 additions and 7 deletions

View file

@ -511,7 +511,7 @@ int cec_thread_func(void *_adap)
pr_warn("cec-%s: transmit timed out\n", adap->name);
}
adap->transmit_in_progress = false;
adap->tx_timeouts++;
adap->tx_timeout_cnt++;
goto unlock;
}
@ -625,6 +625,33 @@ void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
msg->tx_low_drive_cnt += low_drive_cnt;
msg->tx_error_cnt += error_cnt;
adap->tx_arb_lost_cnt += arb_lost_cnt;
adap->tx_low_drive_cnt += low_drive_cnt;
adap->tx_error_cnt += error_cnt;
/*
* Low Drive transmission errors should really not happen for
* well-behaved CEC devices and proper HDMI cables.
*
* Ditto for the 'Error' status.
*
* For the first few times that this happens, log this.
* Stop logging after that, since that will not add any more
* useful information and instead it will just flood the kernel log.
*/
if (done && adap->tx_low_drive_log_cnt < 8 && msg->tx_low_drive_cnt) {
adap->tx_low_drive_log_cnt++;
dprintk(0, "low drive counter: %u (seq %u: %*ph)\n",
msg->tx_low_drive_cnt, msg->sequence,
msg->len, msg->msg);
}
if (done && adap->tx_error_log_cnt < 8 && msg->tx_error_cnt) {
adap->tx_error_log_cnt++;
dprintk(0, "error counter: %u (seq %u: %*ph)\n",
msg->tx_error_cnt, msg->sequence,
msg->len, msg->msg);
}
/* Mark that we're done with this transmit */
adap->transmitting = NULL;
@ -1607,6 +1634,8 @@ int cec_adap_enable(struct cec_adapter *adap)
if (enable) {
adap->last_initiator = 0xff;
adap->transmit_in_progress = false;
adap->tx_low_drive_log_cnt = 0;
adap->tx_error_log_cnt = 0;
ret = adap->ops->adap_enable(adap, true);
if (!ret) {
/*
@ -2265,10 +2294,25 @@ int cec_adap_status(struct seq_file *file, void *priv)
if (adap->monitor_pin_cnt)
seq_printf(file, "file handles in Monitor Pin mode: %u\n",
adap->monitor_pin_cnt);
if (adap->tx_timeouts) {
seq_printf(file, "transmit timeouts: %u\n",
adap->tx_timeouts);
adap->tx_timeouts = 0;
if (adap->tx_timeout_cnt) {
seq_printf(file, "transmit timeout count: %u\n",
adap->tx_timeout_cnt);
adap->tx_timeout_cnt = 0;
}
if (adap->tx_low_drive_cnt) {
seq_printf(file, "transmit low drive count: %u\n",
adap->tx_low_drive_cnt);
adap->tx_low_drive_cnt = 0;
}
if (adap->tx_arb_lost_cnt) {
seq_printf(file, "transmit arbitration lost count: %u\n",
adap->tx_arb_lost_cnt);
adap->tx_arb_lost_cnt = 0;
}
if (adap->tx_error_cnt) {
seq_printf(file, "transmit error count: %u\n",
adap->tx_error_cnt);
adap->tx_error_cnt = 0;
}
data = adap->transmitting;
if (data)

View file

@ -207,7 +207,20 @@ struct cec_adap_ops {
* passthrough mode.
* @log_addrs: current logical addresses
* @conn_info: current connector info
* @tx_timeouts: number of transmit timeouts
* @tx_timeout_cnt: count the number of Timed Out transmits.
* Reset to 0 when this is reported in cec_adap_status().
* @tx_low_drive_cnt: count the number of Low Drive transmits.
* Reset to 0 when this is reported in cec_adap_status().
* @tx_error_cnt: count the number of Error transmits.
* Reset to 0 when this is reported in cec_adap_status().
* @tx_arb_lost_cnt: count the number of Arb Lost transmits.
* Reset to 0 when this is reported in cec_adap_status().
* @tx_low_drive_log_cnt: number of logged Low Drive transmits since the
* adapter was enabled. Used to avoid flooding the kernel
* log if this happens a lot.
* @tx_error_log_cnt: number of logged Error transmits since the adapter was
* enabled. Used to avoid flooding the kernel log if this
* happens a lot.
* @notifier: CEC notifier
* @pin: CEC pin status struct
* @cec_dir: debugfs cec directory
@ -262,7 +275,12 @@ struct cec_adapter {
struct cec_log_addrs log_addrs;
struct cec_connector_info conn_info;
u32 tx_timeouts;
u32 tx_timeout_cnt;
u32 tx_low_drive_cnt;
u32 tx_error_cnt;
u32 tx_arb_lost_cnt;
u32 tx_low_drive_log_cnt;
u32 tx_error_log_cnt;
#ifdef CONFIG_CEC_NOTIFIER
struct cec_notifier *notifier;