Hi Marc,

I answered too quickly in one paragraph.

On Tue. 17 Aug 2021 at 00:49, Vincent MAILHOL
[off-list ref] wrote:

On Mon. 16 Aug 2021 at 22:43, Marc Kleine-Budde [off-list ref] wrote:

...

quoted

Oh, I just noticed:

| ip link set dev mcp251xfd0 down; \
| ip link set mcp251xfd0 txqueuelen 10 up type can \
|     sample-point 0.8 bitrate 500000  \
|     dsample-point 0.8 dbitrate 2000000 fd on \
|     tdc-mode manual tdco 11 tdcv 22

followed by:

| ip link set dev mcp251xfd0 down; \
| ip link set mcp251xfd0 txqueuelen 10 up type can

We stay in manual mode:

| Aug 16 15:27:47 rpi4b8 kernel: mcp251xfd spi0.0 mcp251xfd0: mcp251xfd_set_bittiming: tdco=11 tdcv=22 mode=manual

| 8: mcp251xfd0: <NOARP,UP,LOWER_UP,ECHO> mtu 72 qdisc pfifo_fast state UP mode DEFAULT group default qlen 10
|     link/can  promiscuity 0 minmtu 0 maxmtu 0
|     can <FD,TDC_AUTO,TDC_MANUAL> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 100

That's a bug. It should be impossible to have both TDC_AUTO and
TDC_MANUAL at the same time.

quoted

|           bitrate 500000 sample-point 0.800
|           tq 25 prop-seg 31 phase-seg1 32 phase-seg2 16 sjw 1 brp 1
|           mcp251xfd: tseg1 2..256 tseg2 1..128 sjw 1..128 brp 1..256 brp_inc 1
|           dbitrate 2000000 dsample-point 0.800
|           dtq 25 dprop-seg 7 dphase-seg1 8 dphase-seg2 4 dsjw 1 dbrp 1
|           tdcv 22 tdco 11
|           mcp251xfd: dtseg1 1..32 dtseg2 1..16 dsjw 1..16 dbrp 1..256 dbrp_inc 1
|           tdcv 0..63 tdco 0..63
|           clock 40000000 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 parentbus spi parentdev spi0.0

Sorry, but can I confirm what you did here? You stated that you
did those four commands in this order:

quoted

| ip link set dev mcp251xfd0 down; \
| ip link set mcp251xfd0 txqueuelen 10 up type can \
|     sample-point 0.8 bitrate 500000  \
|     dsample-point 0.8 dbitrate 2000000 fd on \
|     tdc-mode manual tdco 11 tdcv 22
| ip link set dev mcp251xfd0 down; \
| ip link set mcp251xfd0 txqueuelen 10 up type can

So now, you should be in Classical CAN (fd flag off) but the
results of iproute2 shows that FD is on... Is there one missing
step?

Please ignore this part. I misread the latest command and thought
you were configuring it as classical CAN. You just did a network
down / up.

I will troubleshoot this tomorrow.

quoted

I have to give "fd on" + the bit timing parameters to go to the full
automatic mode again:

| Aug 16 15:32:46 rpi4b8 kernel: mcp251xfd spi0.0 mcp251xfd0: mcp251xfd_set_bittiming: tdco=16 tdcv=22 mode=automatic

Yours sincerely,
Vincent