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Ubuntu 18.04.5 LTS
Recently, after kernel update 4.15.0.144 (didn't know about the case yet), i
can't open serial ports on USB CDC devices (STM32 Virtual COMs in my case).
using simple cat command (with or without sudo):
$ sudo cat /dev/ttyACM1
cat: /dev/ttyACM1: Input/output error
or some serial programs:
Failed to connect to /dev/ttyACM1 : [Errno 5] could not open port /dev/ttyACM1:
[Errno 5] Input/output error: '/dev/ttyACM1'
dmesg:
[ 3295.718270] cdc_acm 1-2:1.0: ttyACM1: USB ACM device
[ 3302.508356] cdc_acm 1-2:1.0: acm_port_activate - usb_submit_urb(ctrl irq)
failed
[ 3302.508940] cdc_acm 1-2:1.0: acm_port_activate - usb_submit_urb(ctrl irq)
failed
When i try spamming commands while plugging the device in, i am
sometimes able to open the port (might be the clue).
When i booted in ubuntu advanced mode to 4.15.0.143 kernel, everything
started to work normally.
Also tried HWE stack with 5.4.0.74 kernel, but the bug was also present
there.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: acm bot-comment cdc port serial usb
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cdc_acm: acm_port_activate - usb_submit_urb(ctrl irq) failed
https://bugs.launchpad.net/bugs/1931684
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