cdc-acm: Add DISABLE_ECHO quirk for Microchip/SMSC chip

USB_DEVICE(0x0424, 0x274e) can send data before cdc_acm is ready,
causing garbage chars on the TTY causing stray input to the shell
and/or login prompt.

Signed-off-by: Joakim Tjernlund <[e-mail]>
Cc: [e-mail]
Acked-by: Oliver Neukum <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/class/cdc-acm.c

···
 
 static const struct usb_device_id acm_ids[] = {
 	/* quirky and broken devices */
+	{ USB_DEVICE(0x0424, 0x274e), /* Microchip Technology, Inc. (formerly SMSC) */
+	  .driver_info = DISABLE_ECHO, }, /* DISABLE ECHO in termios flag */
 	{ USB_DEVICE(0x076d, 0x0006), /* Denso Cradle CU-321 */
 	.driver_info = NO_UNION_NORMAL, },/* has no union descriptor */
 	{ USB_DEVICE(0x17ef, 0x7000), /* Lenovo USB modem */