[PATCH] usb: core: allow zero packet flag for interrupt urbs

From: Amit Virdi
Date: Thu Jul 17 2014 - 04:48:43 EST


Section 4.4.7.2 of the USB3.0 spec says:
A zero-length data payload is a valid transfer and may be useful for
some implementations.

So, extend the logic of allowing URB_ZERO_PACKET to interrupt urbs too.
Otherwise, the kernel throws error of BOGUS transfer flags.

Signed-off-by: Amit Virdi <amit.virdi@xxxxxx>
---
drivers/usb/core/urb.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 991386c..a136246 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -460,6 +460,10 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
case USB_ENDPOINT_XFER_CONTROL:
allowed |= URB_NO_FSBR; /* only affects UHCI */
/* FALLTHROUGH */
+ case USB_ENDPOINT_XFER_INT:
+ if (is_out)
+ allowed |= URB_ZERO_PACKET;
+ /* FALLTHROUGH */
default: /* all non-iso endpoints */
if (!is_out)
allowed |= URB_SHORT_NOT_OK;
--
1.8.0

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