greybus: es1/es2: set transfer flag to send a zero-length packet

Greybus messages with a multiple size of 512B generate timeouts
(any other message size doesn't).
512B is exactly the packet size of a bulk out endpoint.
Hence USB device is expecting a short (< 512B)
or zero-length packet to finish the transfer,
which is never generated and causes the timeout.

Set the transfer flag to send a zero-length packet in this situation.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Reviewed-by: Patrick Titiano <ptitiano@baylibre.com>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>

diff --git a/drivers/staging/greybus/es1.c b/drivers/staging/greybus/es1.c
index 2aa2717..ddc26de 100644 (file)
--- a/drivers/staging/greybus/es1.c
+++ b/drivers/staging/greybus/es1.c
@@ -216,6 +216,7 @@ static int message_send(struct greybus_host_device *hd, u16 cport_id,
                          usb_sndbulkpipe(udev, es1->cport_out_endpoint),
                          message->buffer, buffer_size,
                          cport_out_callback, message);
+       urb->transfer_flags |= URB_ZERO_PACKET;
        gb_connection_push_timestamp(message->operation->connection);
        retval = usb_submit_urb(urb, gfp_mask);
        if (retval) {

diff --git a/drivers/staging/greybus/es2.c b/drivers/staging/greybus/es2.c
index 008685b..295cc68 100644 (file)
--- a/drivers/staging/greybus/es2.c
+++ b/drivers/staging/greybus/es2.c
@@ -312,6 +312,7 @@ static int message_send(struct greybus_host_device *hd, u16 cport_id,
                                          es1->cport_out[bulk_ep_set].endpoint),
                          message->buffer, buffer_size,
                          cport_out_callback, message);
+       urb->transfer_flags |= URB_ZERO_PACKET;
        gb_connection_push_timestamp(message->operation->connection);
        retval = usb_submit_urb(urb, gfp_mask);
        if (retval) {