[v2 PATCH] usb: xhci-mtk: fix the failure of bandwidth allocation

[Chunfeng Yun]

The wMaxPacketSize field of endpoint descriptor may be zero
as default value in alternate interface, and they are not
actually selected when start stream, so skip them when try to
allocate bandwidth.

Cc: stable <stable at vger.kernel.org>
Fixes: 0cbd4b34cda9("xhci: mediatek: support MTK xHCI host controller")
Signed-off-by: Chunfeng Yun <chunfeng.yun at mediatek.com>
---
V2: add Fixes suggested by Nicolas
---
 drivers/usb/host/xhci-mtk-sch.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index fea5555..45c54d56 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -557,6 +557,10 @@ static bool need_bw_sch(struct usb_host_endpoint *ep,
 	if (is_fs_or_ls(speed) && !has_tt)
 		return false;
 
+	/* skip endpoint with zero maxpkt */
+	if (usb_endpoint_maxp(&ep->desc) == 0)
+		return false;
+
 	return true;
 }
 
-- 
1.9.1