usb: gadget: uvc: fix interval_duration calculation

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>

diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 7cea641b06b415102f13b101d1c935082e907a45..2f9700b3f1b64fd2acb4c6c93133793c6c531cb3 100644 (file)
--- 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