[PATCH 6.18 145/333] usb: gadget: uvc: fix interval_duration calculation

Greg Kroah-Hartman
2026-03-17T17:17:54Z

From: Junzhong Pan <panjunzhong@linux.spacemit.com>

commit 56135c0c60b07729401af9d329fa9c0eded845a6 upstream.

To correctly convert bInterval as interval_duration:
interval_duration = 2^(bInterval-1) * frame_interval

Current code uses a wrong left shift operand, computing 2^bInterval
instead of 2^(bInterval-1).

Fixes: 010dc57cb516 ("usb: gadget: uvc: fix interval_duration calculation")
Cc: stable <stable@kernel.org>
Signed-off-by: Junzhong Pan <panjunzhong@linux.spacemit.com>
Reviewed-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://patch.msgid.link/20260306-fix-uvc-interval-v1-1-9a2df6859859@linux.spacemit.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/gadget/function/uvc_video.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 7cea641b06b4..2f9700b3f1b6 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -513,7 +513,7 @@ uvc_video_prep_requests(struct uvc_video *video)
return;
}

- interval_duration = 2 << (video->ep->desc->bInterval - 1);
+ interval_duration = 1 << (video->ep->desc->bInterval - 1);
if (cdev->gadget->speed < USB_SPEED_HIGH)
interval_duration *= 10000;
else
--
2.53.0