Re: Accessing I2C-Bus via ELV USB-I2C

From: Hans Petter Selasky <>
Date: Thu, 06 Oct 2022 11:56:06 UTC
On 10/5/22 18:31, Axel Rau wrote:
>> Am 05.10.2022 um 16:46 schrieb Hans Petter Selasky <>:
>> On 10/5/22 13:55, Axel Rau wrote:
>>> If I do not want to touch th USB stuff, can I get the same effect by close/open of the serial device?
>> The uslcom driver only does this right after attach, in 13-stable and 14-main.
>> Does the attached patch make any difference for you?
>> --HPS
>> <0001-uslcom-4-Clear-stall-at-every-open.patch>
> As this is a production server, I try to avoid reboots.
> Meanwhile, I have inserted a read loop which eats the fragments
> and allows the following status query to get a clean response.
> With this patch, recovery seems to work.
> Additionally I have eliminated a hub and connected the device directly to a port.
> Hopefully this will stop the frequent `/dev/cuaU0: Bus connection lost`events.
> Thanks for your time,
> Axel
> ---
> PGP-Key: CDE74120  ☀  computing @ chaos claudius


You just need to rebuild the uslcom.ko and kldunload it.

make -C /usr/src/sys/modules/usb/uslcom all install KMODDIR=/boot/kernel

Anyway, here you go: