]> git.ipfire.org Git - thirdparty/kernel/linux.git/commit
usb: cdc-acm: Restore CAP_BRK functionnality to CH343
authorMarc Zyngier <maz@kernel.org>
Sun, 1 Mar 2026 12:44:40 +0000 (12:44 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 11 Mar 2026 15:17:55 +0000 (16:17 +0100)
commit14ae24cba291bddfdc296bbcbfd00cd09d0498ef
tree523ae8f49388dd46bf6effd599817f2d80451a3d
parent8479891d1f04a8ce55366fe4ca361ccdb96f02e1
usb: cdc-acm: Restore CAP_BRK functionnality to CH343

The CH343 USB/serial adapter is as buggy as it is popular (very).
One of its quirks is that despite being capable of signalling a
BREAK condition, it doesn't advertise it.

This used to work nonetheless until 66aad7d8d3ec5 ("usb: cdc-acm:
return correct error code on unsupported break") applied some
reasonable restrictions, preventing breaks from being emitted on
devices that do not advertise CAP_BRK.

Add a quirk for this particular device, so that breaks can still
be produced on some of my machines attached to my console server.

Fixes: 66aad7d8d3ec5 ("usb: cdc-acm: return correct error code on unsupported break")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable <stable@kernel.org>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Oliver Neukum <oneukum@suse.com>
Link: https://patch.msgid.link/20260301124440.1192752-1-maz@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/class/cdc-acm.c
drivers/usb/class/cdc-acm.h