> -----Original Message-----
> From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
> Sent: 2019年11月11日 18:09
> To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; sean@xxxxxxxxxx;
> linux-can@xxxxxxxxxxxxxxx
> Subject: Re: Wake up issue about Flexcan driver in v5.4 kernel
>
> On 11/11/19 10:48 AM, Joakim Zhang wrote:
> > I came across a strange phenomenon about wake up in Flexcan driver
> > with
> > v5.4 kernel, I connected two i.MX7D-SDB board.
> >
> > I found that CAN frame which try to wake up the system will not be
> > received at another side in order. Like below case:
> >
> > Sender: cangen can0 -vv
> > can0 4D9 [8] 89 72 0C 5F C8 15 2D 3A
> > can0 0AA [8] B7 DC 14 61 7F A0 8E 40
> > can0 304 [8] 42 5C D7 3B D6 1D 36 56
> > can0 0D9 [7] B0 C3 1B 7B 9B 3A 19
> > can0 66B [8] 8A B0 D9 56 00 46 76 48
> > can0 22D [8] 44 4B FD 53 B2 D3 A5 33
> > can0 47E [8] B9 6B 72 0B 4C 15 96 72
> > can0 54C [3] 3F BE 8F
> > can0 7C1 [8] EE A7 B4 11 6C 80 8F 7D
> > can0 5D6 [5] EB 20 1E 3E DB
> > can0 794 [8] B1 56 9E 13 6D 88 CE 52
> > can0 584 [1] 08
> >
> >
> >
> > Receiver: candump can0 &
> > can0 0AA [8] B7 DC 14 61 7F A0 8E 40
> > can0 304 [8] 42 5C D7 3B D6 1D 36 56
> > can0 0D9 [7] B0 C3 1B 7B 9B 3A 19
> > can0 66B [8] 8A B0 D9 56 00 46 76 48
> > can0 22D [8] 44 4B FD 53 B2 D3 A5 33
> > can0 4D9 [8] 89 72 0C 5F C8 15 2D 3A
> > can0 47E [8] B9 6B 72 0B 4C 15 96 72
> > can0 54C [3] 3F BE 8F
> > can0 7C1 [8] EE A7 B4 11 6C 80 8F 7D
> > can0 5D6 [5] EB 20 1E 3E DB
> > can0 794 [8] B1 56 9E 13 6D 88 CE 52
> > can0 584 [1] 08
> >
> > You can see that wake up frame(can0 4D9 [8] 89 72 0C 5F C8 15 2D
> > 3A) will be received at 6^th , it’s hard to understand.
>
> - What did you do before wakeup?
> - Clean reboot?
> - ifdown/ifup?
> - sending other packets?
> - Does this happen on every wakeup?
> - Is the wake up frame always "received" as 6th frame?
> - Is the situation the same, if you add some delay between the frames,
> using the "cangen -g option"?
> - How big can you make the -g until the frames are received in order
> again?
>
> The reception path works like this:
> In the interrupt handler the rx-offload reads all mailboxes based on the iflag
> register. It iterates over all set mailboxes, starting with the first. All mailboxes
> are read including the rx-timestamp, sorted and added into a queue. At the end
> of the IRQ handler the queue is added to the per device queue thats read in the
> NAPI and pushed into the networking stack.
>
> Maybe something with the timestamp of the first packet is wrong, as the
> counter is only 16 bits wide, it will overflow quite often.
>
> Maybe you can trace_printk the mailbox number, timestamp and can_id in
> mailbox_read() and analyse output after wakeup. Feel free to post the output
> of the tracer here.
Hi Marc,
I dump some info in wake up case from v5.3.10 with below change:
printk("\nmailbox_num = %u, timestamp = %u, can_id = %x\n", n, *timestamp, cf->can_id);
1)
Sender: cangen can0 -vv
can0 266 [8] F2 2D C6 5F 0E FE DE 38
can0 71E [8] 8A F0 C5 2F 9F 3C 72 32
can0 256 [2] 03 4B
can0 6FC [8] B1 46 D5 40 F6 C4 CC 1D
can0 21A [2] 60 2C
can0 594 [2] B1 5A
can0 162 [2] CB 41
can0 6B0 [4] CA 64 AB 70
can0 710 [8] 25 27 2F 11 2F 76 54 17
can0 50B [8] CE B2 C6 49 61 1F B9 3A
Receiver: candump can0 &
mailbox_num = 1, timestamp = 4113563648, can_id = 266
mailbox_num = 2, timestamp = 4105568256, can_id = 71e
mailbox_num = 3, timestamp = 43646976, can_id = 256
mailbox_num = 4, timestamp = 276496384, can_id = 6fc
mailbox_num = 5, timestamp = 509149184, can_id = 21a
mailbox_num = 6, timestamp = 741605376, can_id = 594
mailbox_num = 1, timestamp = 973406208, can_id = 162
mailbox_num = 1, timestamp = 1205010432, can_id = 6b0
mailbox_num = 1, timestamp = 1437138944, can_id = 710
mailbox_num = 1, timestamp = 1670184960, can_id = 50b
can0 71E [8] 8A F0 C5 2F 9F 3C 72 32
can0 266 [8] F2 2D C6 5F 0E FE DE 38
can0 256 [2] 03 4B
can0 6FC [8] B1 46 D5 40 F6 C4 CC 1D
can0 21A [2] 60 2C
can0 594 [2] B1 5A
can0 162 [2] CB 41
can0 6B0 [4] CA 64 AB 70
can0 710 [8] 25 27 2F 11 2F 76 54 17
can0 50B [8] CE B2 C6 49 61 1F B9 3A
2)
Sender: cangen can0 -g 100 -vv
can0 343 [4] 13 89 21 5D
can0 2DF [8] E6 64 C6 25 ED F0 7B 16
can0 353 [8] 9B 84 9B 21 CA A3 CC 50
can0 4E2 [8] 63 0E B0 1E 70 0E C2 12
can0 643 [4] 75 9E 6E 08
can0 3D1 [5] E9 A6 FE 1D 88
can0 4E6 [8] A3 02 0E 08 1B F1 32 4F
can0 6E2 [1] 1B
can0 026 [8] 08 36 25 73 05 BB F3 4F
can0 1CD [8] F3 AB 6F 66 20 ED B2 46
can0 157 [8] EB 90 7F 17 39 0E E7 48
can0 227 [8] A9 1C A9 5B 6B 78 7D 33
can0 6D2 [8] A3 E3 01 56 A3 3A AB 3C
can0 2D4 [8] 2C F5 A4 62 BA C7 6E 7D
can0 416 [8] D5 B8 A1 4C F8 E2 EF 0A
can0 6B0 [1] 1E
can0 620 [6] DC 01 4F 77 ED 1F
can0 615 [8] 0D 0D 98 68 6C E7 EF 06
can0 65D [8] A5 F5 D6 4F 85 D0 9B 14
can0 546 [8] F0 48 19 48 18 C4 DA 53
can0 56D [3] BC FE 85
can0 71F [8] FB 57 77 5D 35 AB E6 73
Receiver: candump can0 &
mailbox_num = 1, timestamp = 1521614848, can_id = 343
mailbox_num = 2, timestamp = 3618439168, can_id = 2df
mailbox_num = 3, timestamp = 1590951936, can_id = 353
mailbox_num = 4, timestamp = 3859611648, can_id = 4e2
mailbox_num = 5, timestamp = 1833238528, can_id = 643
mailbox_num = 6, timestamp = 4101767168, can_id = 3d1
mailbox_num = 7, timestamp = 2076770304, can_id = 4e6
mailbox_num = 8, timestamp = 50135040, can_id = 6e2
mailbox_num = 9, timestamp = 2318729216, can_id = 26
mailbox_num = 10, timestamp = 291897344, can_id = 1cd
mailbox_num = 11, timestamp = 2559901696, can_id = 157
mailbox_num = 12, timestamp = 532742144, can_id = 227
mailbox_num = 1, timestamp = 2801336320, can_id = 6d2
mailbox_num = 1, timestamp = 776011776, can_id = 2d4
mailbox_num = 1, timestamp = 3044343808, can_id = 416
mailbox_num = 1, timestamp = 1016332288, can_id = 6b0
can0 343 [4] 13 89 21 5D
can0 353 [8] 9B 84 9B 21 CA A3 CC 50
can0 643 [4] 75 9E 6E 08
can0 4E6 [8] A3 02 0E 08 1B F1 32 4F
can0 026 [8] 08 36 25 73 05 BB F3 4F
can0 157 [8] EB 90 7F 17 39 0E E7 48
can0 2DF [8] E6 64 C6 25 ED F0 7B 16
can0 4E2 [8] 63 0E B0 1E 70 0E C2 12
can0 3D1 [5] E9 A6 FE 1D 88
can0 6E2 [1] 1B
can0 1CD [8] F3 AB 6F 66 20 ED B2 46
can0 227 [8] A9 1C A9 5B 6B 78 7D 33
can0 6D2 [8] A3 E3 01 56 A3 3A AB 3C
can0 2D4 [8] 2C F5 A4 62 BA C7 6E 7D
can0 416 [8] D5 B8 A1 4C F8 E2 EF 0A
can0 6B0 [1] 1E
I found that not only the wake up frame will out-of-order, frames read in one round including wake up frame all could be disordered.
Best Regards,
Joakim Zhang
> regards,
> Marc
>
> --
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