[PATCH 3.16 079/178] usb: gadget: f_uvc: Fix SuperSpeed companion descriptor's wBytesPerInterval
From: Ben Hutchings
Date: Sun Jul 16 2017 - 10:15:20 EST
3.16.46-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Roger Quadros <rogerq@xxxxxx>
commit 09424c50b7dff40cb30011c09114404a4656e023 upstream.
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.
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Roger Quadros <rogerq@xxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/usb/gadget/f_uvc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/usb/gadget/f_uvc.c
+++ b/drivers/usb/gadget/f_uvc.c
@@ -625,7 +625,7 @@ uvc_function_bind(struct usb_configurati
uvc_ss_streaming_comp.bMaxBurst = streaming_maxburst;
uvc_ss_streaming_comp.wBytesPerInterval =
cpu_to_le16(max_packet_size * max_packet_mult *
- streaming_maxburst);
+ (streaming_maxburst + 1));
/* Allocate endpoints. */
ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);