This is a note to let you know that I've just added the patch titled USB: cdc-acm: downgrade message to debug to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-cdc-acm-downgrade-message-to-debug.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From e4c77070ad45fc940af1d7fb1e637c349e848951 Mon Sep 17 00:00:00 2001 From: Oliver Neukum <oneukum@xxxxxxxx> Date: Thu, 11 Mar 2021 14:01:26 +0100 Subject: USB: cdc-acm: downgrade message to debug From: Oliver Neukum <oneukum@xxxxxxxx> commit e4c77070ad45fc940af1d7fb1e637c349e848951 upstream. This failure is so common that logging an error here amounts to spamming log files. Reviewed-by: Bruno Thomsen <bruno.thomsen@xxxxxxxxx> Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210311130126.15972-2-oneukum@xxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/class/cdc-acm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -676,7 +676,8 @@ static void acm_port_dtr_rts(struct tty_ res = acm_set_control(acm, val); if (res && (acm->ctrl_caps & USB_CDC_CAP_LINE)) - dev_err(&acm->control->dev, "failed to set dtr/rts\n"); + /* This is broken in too many devices to spam the logs */ + dev_dbg(&acm->control->dev, "failed to set dtr/rts\n"); } static int acm_port_activate(struct tty_port *port, struct tty_struct *tty) Patches currently in stable-queue which might be from oneukum@xxxxxxxx are queue-4.14/usb-cdc-acm-untangle-a-circular-dependency-between-callback-and-softint.patch queue-4.14/usb-cdc-acm-downgrade-message-to-debug.patch queue-4.14/cdc-acm-fix-break-rx-code-path-adding-necessary-calls.patch queue-4.14/usb-cdc-acm-fix-use-after-free-after-probe-failure.patch