2 files changed, 11 insertions, 0 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 1b68fed464cb..ed8c62b2d9d1 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -581,6 +581,13 @@ static int acm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
         if (retval)
                 goto error_init_termios;
 
+        /*
+         * Suppress initial echoing for some devices which might send data
+         * immediately after acm driver has been installed.
+         */
+        if (acm->quirks & DISABLE_ECHO)
+                tty->termios.c_lflag &= ~ECHO;
+
         tty->driver_data = acm;
 
         return 0;
@@ -1657,6 +1664,9 @@ static const struct usb_device_id acm_ids[] = {
         { USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */
         .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
         },
+        { USB_DEVICE(0x0e8d, 0x2000), /* MediaTek Inc Preloader */
+        .driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */
+        },
         { USB_DEVICE(0x0e8d, 0x3329), /* MediaTek Inc GPS */
         .driver_info = NO_UNION_NORMAL, /* has no union descriptor */
         },
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index ca06b20d7af9..515aad0847ee 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -140,3 +140,4 @@ struct acm {
 #define QUIRK_CONTROL_LINE_STATE        BIT(6)
 #define CLEAR_HALT_CONDITIONS           BIT(7)
 #define SEND_ZERO_PACKET                BIT(8)
+#define DISABLE_ECHO                    BIT(9)