usb: cdc-acm: send zero packet for intel 7260 modem

commit ffdb1e3 upstream. For Intel 7260 modem, it is needed for host side to send zero packet if the BULK OUT size is equal to USB endpoint max packet length. Otherwise, modem side may still wait for more data and cannot give response to host side. Signed-off-by: Konrad Leszczynski <[email protected]> Signed-off-by: Lu Baolu <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
openbmc · Feb 19, 2016 · 0db18da · 0db18da
1 parent 8b49e8a
commit 0db18da
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diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
@@ -1405,6 +1405,8 @@ static int acm_probe(struct usb_interface *intf,
 				usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
 				NULL, acm->writesize, acm_write_bulk, snd);
 		snd->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+		if (quirks & SEND_ZERO_PACKET)
+			snd->urb->transfer_flags |= URB_ZERO_PACKET;
 		snd->instance = acm;
 	}
 
@@ -1862,6 +1864,10 @@ static const struct usb_device_id acm_ids[] = {
 	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
 		USB_CDC_ACM_PROTO_AT_CDMA) },
 
+	{ USB_DEVICE(0x1519, 0x0452), /* Intel 7260 modem */
+	.driver_info = SEND_ZERO_PACKET,
+	},
+
 	{ }
 };
 

diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
@@ -134,3 +134,4 @@ struct acm {
 #define IGNORE_DEVICE			BIT(5)
 #define QUIRK_CONTROL_LINE_STATE	BIT(6)
 #define CLEAR_HALT_CONDITIONS		BIT(7)
+#define SEND_ZERO_PACKET		BIT(8)