AGX Orin: CAN bus does not recover from BUS_OFF state

tim117 · October 25, 2023, 12:03pm

thanks for the quick reply! I indeed missed step 8, so now I can actually see the prints I added to the function. Unfortunately, after the down&up, the cangen can0 runs for a little while and then shows the “no buffer space available” error again.

Here’s the output when I’m following your steps:

$ sudo modprobe mttcan

$ sudo ip link set can0 up type can bitrate 100000 berr-reporting on restart-ms 1000
RTNETLINK answers: Device or resource busy
# don't know if above error is a problem?

$ cangen can0
# runs fine, now short CAN-H/CAN-L
write: No buffer space available
# ... stop shorting

$ sudo ip -d -s link show can0
12: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP mode DEFAULT group default qlen 10
    link/can  promiscuity 0 minmtu 0 maxmtu 0
    can <BERR-REPORTING> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 1000
          bitrate 500000 sample-point 0.870
          tq 20 prop-seg 43 phase-seg1 43 phase-seg2 13 sjw 1
          mttcan: tseg1 2..255 tseg2 0..127 sjw 1..127 brp 1..511 brp-inc 1
          mttcan: dtseg1 1..31 dtseg2 0..15 dsjw 1..15 dbrp 1..15 dbrp-inc 1
          clock 50000000
          re-started bus-errors arbit-lost error-warn error-pass bus-off
          2          6          0          2          2          2         numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
    RX: bytes  packets  errors  dropped overrun mcast
    4980525    689926   6       0       0       0
    TX: bytes  packets  errors  dropped carrier collsns
    1129       198      0       0       0       0

$ cangen can0
write: No buffer space available

$ sudo ip link set can0 down
$ sudo ip link set can0 up type can bitrate 100000 berr-reporting on restart-ms 1000

$ cangen can0
# runs for a couple of seconds but then prints this again
write: No buffer space available

When looking at dmesg, you can see that the patch is there (I printed each line):

$ sudo dmesg
[ 3430.899903] mttcan c310000.mttcan can0: entered error warning state
[ 3430.906431] mttcan c310000.mttcan can0: entered error passive state
[ 3430.912903] mttcan c310000.mttcan can0: Bit0 Error Detected
[ 3430.918664] mttcan c310000.mttcan can0: IR 0x9800000 PSR 0x77d
[ 3430.924713] mttcan c310000.mttcan can0: entered bus off state
[ 3430.931473] mttcan c310000.mttcan can0: Bit0 Error Detected
[ 3430.937252] mttcan c310000.mttcan can0: IR 0xa000000 PSR 0x7e5
[ 3431.950397] mttcan_controller_config: ctrlmode 10
[ 3431.950423] mttcan c310000.mttcan can0: Bitrate set
[ 3431.950434] mttcan c310000.mttcan can0: wait for bus off seq
[ 3431.962506] mttcan c310000.mttcan can0: Bit0 Error Detected
[ 3431.968252] mttcan c310000.mttcan can0: IR 0xa000000 PSR 0x70d
[ 3431.974301] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
[ 3432.101006] mttcan c310000.mttcan can0: entered error warning state
[ 3432.107504] mttcan c310000.mttcan can0: entered error passive state
[ 3432.113967] mttcan c310000.mttcan can0: Bit0 Error Detected
[ 3432.119722] mttcan c310000.mttcan can0: IR 0x9800000 PSR 0x76d
[ 3432.125776] mttcan c310000.mttcan can0: entered bus off state
[ 3432.132509] mttcan c310000.mttcan can0: Bit0 Error Detected
[ 3432.138261] mttcan c310000.mttcan can0: IR 0xa010000 PSR 0x7e5
[ 3433.134369] mttcan_controller_config: ctrlmode 10
[ 3433.134393] mttcan c310000.mttcan can0: Bitrate set
[ 3433.134405] mttcan c310000.mttcan can0: wait for bus off seq
[ 3433.146486] mttcan c310000.mttcan can0: Bit0 Error Detected
[ 3433.152251] mttcan c310000.mttcan can0: IR 0xa000000 PSR 0x70d
[ 3433.158320] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
[ 3562.140557] mttcan c310000.mttcan can0: inside mttcan_close:  netif_stop_queue(dev);
[ 3562.140564] mttcan c310000.mttcan can0: inside mttcan_close: napi_disable(&priv->napi);
[ 3562.140567] mttcan c310000.mttcan can0: inside mttcan_close: mttcan_stop(priv);
[ 3562.140581] mttcan c310000.mttcan can0: inside mttcan_close: free_irq(dev->irq, dev);
[ 3562.140598] mttcan c310000.mttcan can0: inside mttcan_close: priv->ttcan->tx_object = 0;
[ 3562.140600] mttcan c310000.mttcan can0: inside mttcan_close: priv->hwts_rx_en = false;
[ 3576.107601] mttcan c310000.mttcan can0: Bitrate set
[ 3576.107672] mttcan_controller_config: ctrlmode 10
[ 3576.107685] mttcan c310000.mttcan can0: Bitrate set
[ 3576.107747] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready

So not sure why it does not work for us…

KevinFFF · October 27, 2023, 5:27am

Do you have AGX Orin devkit could apply the same patch and verify?

KevinFFF · October 27, 2023, 5:32am

It seems you could send the packet after configuring can down and up.

Do you recover the CAN-H and CAN-L connection before run cangen at the last step? (i.e. do you follow Step 6 to recover CAN connection?)

tim117 · October 27, 2023, 9:09am

Yes, we did use an AGX Orin devkit for the test.

It seems you could send the packet after configuring can down and up.

Do you recover the CAN-H and CAN-L connection before run cangen at the last step? (i.e. do you follow Step 6 to recover CAN connection?)

Yes, we did. Basically ran cangen can0, then shorted and waited until the error appeared. Then released the short and continued with the other steps.

KevinFFF · October 30, 2023, 2:49am

Do you mean that you run Step 4 before Step 3?

Could you help to verify with the exact same steps as I shared?
We should get the same result and on the same stage…

tim117 · November 10, 2023, 9:13am

Sorry for the late reply, I haven’t been able to work on this for a couple of days.

I think I tested multiple variations and it didn’t matter, it never recovered. I’ll be back in office next week though and will test it once again, making sure that I exactly follow your steps in the correct order. Will give you an update then!

lpz_thread · December 27, 2023, 9:46am

We also encountered this problem, but we think it should be restored automatically，our version is R35.4.1

system · January 17, 2024, 2:40am

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