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-rw-r--r--drivers/usb/class/cdc-acm.c10
-rw-r--r--drivers/usb/class/cdc-acm.h1
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)