On 04.05.2021 00:02:49, Vincent MAILHOL wrote: > > > ACK bit in data frame > > > - Some logging hardware can act as a "spy", meaning that it records CAN > > > Frames, but does not set the ACK bit > > > - A way to know for a given frame (FD or not), was the ACK bit set or > > > not. > > > - Current API allow detecting missing ACK, but it does not report what > > > Frame had a missing ACK. > > > > This means the driver has to set a flag if it's configured in > > listen-only mode. That should be possible. > > For my understanding, when a controller does not see the ACK bit, > it stops the transmission and sends an error flag. For this > reason, the frame is not received and thus simply does not appear > in the log. Hmmm. That's not correct for the mcp251xfd in RX-listen only mode: | (2021-05-03 17:11:28.493992) mcp251xfd0 RX - - 222 [8] 05 00 00 00 00 00 00 00 | (2021-05-03 17:11:28.994109) mcp251xfd0 RX - - 222 [8] 06 00 00 00 00 00 00 00 | (2021-05-03 17:11:29.494298) mcp251xfd0 RX - - 222 [8] 07 00 00 00 00 00 00 00 | (2021-05-03 17:11:29.994510) mcp251xfd0 RX - - 222 [8] 08 00 00 00 00 00 00 00 | (2021-05-03 17:11:30.494635) mcp251xfd0 RX - - 222 [8] 09 00 00 00 00 00 00 00 unplugged 3rd device here (that's used to send the ACK) | (2021-05-03 17:11:30.998388) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:30.998662) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:30.998936) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:30.999210) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:30.999484) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:30.999758) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.000032) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.000306) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.000580) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.000854) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.001128) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.001402) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.001676) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.001950) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.002224) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.002498) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.002772) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.003046) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.003320) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:11:31.003594) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 --- The flexcan (can0) does behave differently: | (2021-05-03 17:16:43.004939) can0 RX - - 222 [8] 08 00 00 00 00 00 00 00 | (2021-05-03 17:16:43.005846) mcp251xfd0 RX - - 222 [8] 08 00 00 00 00 00 00 00 | (2021-05-03 17:16:43.505052) can0 RX - - 222 [8] 09 00 00 00 00 00 00 00 | (2021-05-03 17:16:43.505729) mcp251xfd0 RX - - 222 [8] 09 00 00 00 00 00 00 00 | (2021-05-03 17:16:44.005193) can0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 | (2021-05-03 17:16:44.005856) mcp251xfd0 RX - - 222 [8] 0A 00 00 00 00 00 00 00 unplugged 3rd device here (that's used to send the ACK) | (2021-05-03 17:16:44.507358) mcp251xfd0 RX - - 222 [8] 0B 00 00 00 00 00 00 00 | (2021-05-03 17:16:44.507399) mcp251xfd0 RX - - 222 [8] 0B 00 00 00 00 00 00 00 | (2021-05-03 17:16:44.508142) mcp251xfd0 RX - - 222 [8] 0B 00 00 00 00 00 00 00 Thomas, is that worth investigating in your side? regards, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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