[PATCH 4.19 62/86] usb: xhci-mtk: fix the failure of bandwidth allocation

Greg Kroah-Hartman
2020-07-27T14:13:00Z

From: Chunfeng Yun <chunfeng.yun@mediatek.com>

commit 5ce1a24dd98c00a57a8fa13660648abf7e08e3ef upstream.

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@vger.kernel.org>
Fixes: 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1594360672-2076-1-git-send-email-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/host/xhci-mtk-sch.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -275,6 +275,10 @@ static bool need_bw_sch(struct usb_host_
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;
}