Hi Gediminas,

thanks for the information!

I've put info [at] 8devices.com into the recipients list as the Linux 
driver has to do the "right thing" when it gets the "Tx URB aborted 
(-2)" information.

And so far I did not see anything like this with the old 'white' USB2CAN 
adapter with FW 1.7.

As long as we don't know how to react on this new feedback from the USB 
device, it is hard to think about a fix ...

Best regards,
Oliver


On 04/02/2020 20.54, Gediminas Simanskis wrote:

Hi Oliver,

I remember that in some conditions usb2can began to flood with messages 
like this (CANAL_STATUSMSG_xx).
In normal state these messages should be disabled via init string.

I don't have acces to Korlan firmware.

Regards,
Gediminas

On 2020-02-04 19:52, Oliver Hartkopp wrote:

quoted

Hello Gediminas,

I took a look into the old firmware of the former USB_8DEV adapter 
with the white housing which had a CANAL_STATUSMSG_BUSLIGHT (== 0x02) 
return value:

https://github.com/krumboeck/usb2can_firmware/blob/master/main.c#L227

Is this the right place to search for the value that is checked in the 
kernel here:
https://elixir.bootlin.com/linux/v5.5.1/source/drivers/net/can/usb/usb_8dev.c#L581 


??

can0: Tx URB aborted (-2)

At least the status is *only* printed in 
usb_8dev_write_bulk_callback() and the echo skb handling is still 
performed as there was a zero status (== ok?!?).

Do you have an idea how to proceed with the driver in the case the 
user has the newer
https://www.8devices.com/products/usb2can_korlan
device?

Best regards,
Oliver

On 13/12/2019 18.20, Gediminas Simanskis wrote:

quoted

Seems like to USB2CAN buffer overflow and firmware crashing.

Gediminas

On 2019-12-13 18:27, Michal Sojka wrote:

quoted

On Fri, Dec 13 2019, Michal Sojka wrote:

quoted

Hi Oliver,

On Fri, Dec 13 2019, Oliver Hartkopp wrote:

quoted

Did you do anything weird (e.g. pulling the USB plug on the run) 
to get
this problem?

No, I just connected it to an ECU and started sending messages on the
bus. The behaviour was like if the messages were not acknowledged, 
i.e.,
initially, candump on my laptop showed the messages sent, but after 
some
time (perhaps after TX buffers were full), candump stopped. I was also
not able to see any messages sent by the ECU (both before and after I
sent my messages).

When I used the same ECU and all the wiring with peak_usb, 
communication
with the ECU was without any problems.

I did more investigation - I was able to fix the problem by adding a
terminator resistor to the bus.

However, the problem can be easily reproduced by the following sequence
of commands, when the USB2CAN is not connected to any bus:

     ip link set can0 up txqueuelen 1000 type can bitrate 500000
     candump can0
     cangen -v -g 50 can0

when candump stops printing the messages, run:

     ip link set down dev can0

and the warnings appear in dmesg. I was also trying this with latest
mainline kernel, which includes the fix for use-after-free, and the
warnings are still there.

-Michal