kernel/drivers/usb/class/cdc-acm.h, branch linux-rolling-stable

usb: cdc-acm: Restore CAP_BRK functionnality to CH343

2026-03-19T15:15:04Z

commit 14ae24cba291bddfdc296bbcbfd00cd09d0498ef upstream. 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 Cc: stable Cc: Oliver Neukum Cc: Greg Kroah-Hartman Acked-by: Oliver Neukum Link: https://patch.msgid.link/20260301124440.1192752-1-maz@kernel.org Signed-off-by: Greg Kroah-Hartman

USB: cdc-acm: use CDC serial-state defines

2022-07-25T08:57:41Z

Use the new CDC serial-state defines. Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20220725075841.1187-5-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

USB: cdc-acm: use CDC control-line defines

2022-07-25T08:57:41Z

Use the new CDC control-line defines. Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20220725075841.1187-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: remove CMSPAR ifdefs

2022-05-19T16:26:16Z

CMSPAR is defined by all architectures since commit 6bf08cb246b5 ("[PATCH] Add CMSPAR to termbits.h for powerpc and alpha"). Reviewed-by: Johan Hovold Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220513082906.11096-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

USB: cdc-acm: fix minor-number release

2021-09-14T08:33:40Z

If the driver runs out of minor numbers it would release minor 0 and allow another device to claim the minor while still in use. Fortunately, registering the tty class device of the second device would fail (with a stack dump) due to the sysfs name collision so no memory is leaked. Fixes: cae2bc768d17 ("usb: cdc-acm: Decrement tty port's refcount if probe() fail") Cc: stable@vger.kernel.org # 4.19 Cc: Jaejoong Kim Acked-by: Oliver Neukum Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210907082318.7757-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

usb: cdc-acm: fix cooldown mechanism

2020-10-28T12:20:21Z

Commit a4e7279cd1d1 ("cdc-acm: introduce a cool down") is causing regression if there is some USB error, such as -EPROTO. This has been reported on some samples of the Odroid-N2 using the Combee II Zibgee USB dongle. > struct acm *acm = container_of(work, struct acm, work) is incorrect in case of a delayed work and causes warnings, usually from the workqueue: > WARNING: CPU: 0 PID: 0 at kernel/workqueue.c:1474 __queue_work+0x480/0x528. When this happens, USB eventually stops working completely after a while. Also the ACM_ERROR_DELAY bit is never set, so the cooldown mechanism previously introduced cannot be triggered and acm_submit_read_urb() is never called. This changes makes the cdc-acm driver use a single delayed work, fixing the pointer arithmetic in acm_softint() and set the ACM_ERROR_DELAY when the cooldown mechanism appear to be needed. Fixes: a4e7279cd1d1 ("cdc-acm: introduce a cool down") Cc: Oliver Neukum Reported-by: Pascal Vizeli Acked-by: Oliver Neukum Signed-off-by: Jerome Brunet Link: https://lore.kernel.org/r/20201019170702.150534-1-jbrunet@baylibre.com Cc: stable Signed-off-by: Greg Kroah-Hartman

USB: cdc-acm: clean up no-union-descriptor handling

2020-09-25T15:01:12Z

For interfaces that lack a union descriptor, probe for a "combined-interface" before falling back to the call-management descriptor instead of the other way round. This allows for the removal of the NO_DATA_INTERFACE quirk and makes the probe algorithm somewhat easier to follow. Acked-by: Oliver Neukum Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20200921135951.24045-5-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

USB: cdc-acm: use common data-class define

2020-09-25T15:01:12Z

Use the data-class define provided by USB core and drop the driver-specific one. Acked-by: Oliver Neukum Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20200921135951.24045-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

USB: cdc-acm: cleanup of data structures

2020-09-17T16:52:44Z

Buffers should be u8*, not unsigned char* Buffers have an unsigned length and using an int as a boolean is a bit outdated. No functional change intended. Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20200917110235.11854-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

cdc-acm: introduce a cool down

2020-04-16T12:59:49Z

Immediate submission in case of a babbling device can lead to a busy loop. Introducing a delayed work. Signed-off-by: Oliver Neukum Cc: stable Tested-by: Jonas Karlsson Link: https://lore.kernel.org/r/20200415151358.32664-2-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman