[PATCH 1/2] usb: gadget: f_uvc: Fix SuperSpeed companion descriptor's wBytesPerInterval

From: Roger Quadros
Date: Wed Mar 08 2017 - 09:29:30 EST


The streaming_maxburst module parameter is 0 offset (0..15)
so we must add 1 while using it for wBytesPerInterval
calculation for the SuperSpeed companion descriptor.

Without this host uvcvideo driver will always see the wrong
wBytesPerInterval for SuperSpeed uvc gadget and may not find
a suitable video interface endpoint.
e.g. for streaming_maxburst = 0 case it will always
fail as wBytePerInterval was evaluating to 0.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
drivers/usb/gadget/function/f_uvc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 29b41b5..c7689d0 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -625,7 +625,7 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
uvc_ss_streaming_comp.bMaxBurst = opts->streaming_maxburst;
uvc_ss_streaming_comp.wBytesPerInterval =
cpu_to_le16(max_packet_size * max_packet_mult *
- opts->streaming_maxburst);
+ (opts->streaming_maxburst + 1));

/* Allocate endpoints. */
ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);
--
2.7.4