--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -503,9 +503,22 @@
 	unsigned int max_req_size, req_size, header_size;
 	unsigned int nreq;
 
+	pr_info_once("uvc: Video prep enter: video=%p ep=%p max_req=%u max_payload=%u imagesize=%u interval=%u\n",
+		video, video->ep, video->max_req_size, video->max_payload_size,
+		video->imagesize, video->interval);
+
 	max_req_size = video->max_req_size;
 
+	uvcg_info(&uvc->func,
+		"Video prep ep: ep=%p desc=%p maxpacket=%u maxburst=%u mult=%u\n",
+		video->ep, video->ep->desc, video->ep->maxpacket,
+		video->ep->maxburst, video->ep->mult);
+
 	if (!usb_endpoint_xfer_isoc(video->ep->desc)) {
+		uvcg_info(&uvc->func,
+			"Video prep non-isoc: attrs=0x%x max_req=%u imagesize=%u interval=%u\n",
+			video->ep->desc->bmAttributes, max_req_size,
+			video->imagesize, video->interval);
 		video->req_size = max_req_size;
 		video->reqs_per_frame = video->uvc_num_requests =
 			DIV_ROUND_UP(video->imagesize, max_req_size);
@@ -534,6 +547,16 @@
 	}
 	video->req_size = req_size;
 
+	if (!req_size || !video->max_payload_size || !video->imagesize || !nreq) {
+		uvcg_info(&uvc->func,
+			"Video prep requests: imagesize=%u interval=%u interval_dur=%u nreq=%u header=%u req_size=%u max_req=%u max_payload=%u ep_maxpacket=%u maxburst=%u mult=%u bInterval=%u speed=%u\n",
+			video->imagesize, video->interval, interval_duration, nreq,
+			header_size, req_size, max_req_size,
+			video->max_payload_size, video->ep->maxpacket,
+			video->ep->maxburst, video->ep->mult,
+			video->ep->desc->bInterval, cdev->gadget->speed);
+	}
+
 	/* We need to compensate the amount of requests to be
 	 * allocated with the maximum amount of zero length requests.
 	 * Since it is possible that hw_submit will initially
@@ -558,6 +581,11 @@
 	 */
 	uvc_video_prep_requests(video);
 
+	uvcg_info(&video->uvc->func,
+		"Video alloc: req_size=%u max_req=%u max_payload=%u uvc_num_requests=%u reqs_per_frame=%u\n",
+		video->req_size, video->max_req_size, video->max_payload_size,
+		video->uvc_num_requests, video->reqs_per_frame);
+
 	for (i = 0; i < video->uvc_num_requests; i++) {
 		ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL);
 		if (ureq == NULL)
@@ -764,20 +792,78 @@
 {
 	int ret;
 
+	if (!video) {
+		pr_err("uvcg_video_enable: missing video\n");
+		return -EINVAL;
+	}
+
+	if (!video->uvc || !video->uvc->func.config ||
+	    !video->uvc->func.config->cdev) {
+		pr_err("uvcg_video_enable: missing uvc/func/config video=%p uvc=%p\n",
+		       video, video->uvc);
+		return -ENODEV;
+	}
+
 	if (video->ep == NULL) {
 		uvcg_info(&video->uvc->func,
 			  "Video enable failed, device is uninitialized.\n");
 		return -ENODEV;
 	}
 
+	if (!video->ep->desc) {
+		uvcg_err(&video->uvc->func,
+			"Video enable failed, missing ep desc ep=%p maxpacket=%u maxburst=%u mult=%u\n",
+			video->ep, video->ep->maxpacket,
+			video->ep->maxburst, video->ep->mult);
+		return -EINVAL;
+	}
+
+	if (!video->kworker || !video->async_wq) {
+		uvcg_err(&video->uvc->func,
+			"Video enable failed, missing worker(s) kworker=%p async_wq=%p\n",
+			video->kworker, video->async_wq);
+		return -EINVAL;
+	}
+
+	if (!video->queue.queue.dev) {
+		uvcg_err(&video->uvc->func,
+			"Video enable failed, missing queue device\n");
+		return -EINVAL;
+	}
+
 	/*
 	 * Safe to access request related fields without req_lock because
 	 * this is the only thread currently active, and no other
 	 * request handling thread will become active until this function
 	 * returns.
 	 */
+	uvcg_info(&video->uvc->func,
+		"Video enable start: video=%p ep=%p kworker=%p async_wq=%p req_size=%u max_payload=%u requests=%u reqs_per_frame=%u use_sg=%u flags=0x%x\n",
+		video, video->ep, video->kworker, video->async_wq,
+		video->req_size, video->max_payload_size,
+		video->uvc_num_requests, video->reqs_per_frame,
+		video->queue.use_sg, video->queue.flags);
+
 	video->is_enabled = true;
 
+	if (!video->queue.queue.lock || !video->queue.queue.ops ||
+	    !video->queue.queue.mem_ops) {
+		uvcg_err(&video->uvc->func,
+			"Video queue not ready: dev=%p lock=%p ops=%p mem_ops=%p buf_ops=%p drv_priv=%p type=%u io_modes=0x%x\n",
+			video->queue.queue.dev, video->queue.queue.lock,
+			video->queue.queue.ops, video->queue.queue.mem_ops,
+			video->queue.queue.buf_ops, video->queue.queue.drv_priv,
+			video->queue.queue.type, video->queue.queue.io_modes);
+		return -EINVAL;
+	}
+
+	uvcg_info(&video->uvc->func,
+		"Video queue enable: dev=%p lock=%p ops=%p mem_ops=%p buf_ops=%p drv_priv=%p type=%u io_modes=0x%x\n",
+		video->queue.queue.dev, video->queue.queue.lock,
+		video->queue.queue.ops, video->queue.queue.mem_ops,
+		video->queue.queue.buf_ops, video->queue.queue.drv_priv,
+		video->queue.queue.type, video->queue.queue.io_modes);
+
 	if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
 		return ret;
 
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -298,6 +298,14 @@
 	int ret;
 
 	uvcg_info(f, "%s(%u, %u)\n", __func__, interface, alt);
+	uvcg_info(f,
+		"UVC set_alt: intf=%u alt=%u state=%u speed=%u ep=%p desc=%p maxpacket=%u maxburst=%u mult=%u\n",
+		interface, alt, uvc->state, cdev->gadget->speed,
+		uvc->video.ep,
+		uvc->video.ep ? uvc->video.ep->desc : NULL,
+		uvc->video.ep ? uvc->video.ep->maxpacket : 0,
+		uvc->video.ep ? uvc->video.ep->maxburst : 0,
+		uvc->video.ep ? uvc->video.ep->mult : 0);
 
 	if (interface == uvc->control_intf) {
 		if (alt)
@@ -362,10 +370,34 @@
 			return ret;
 		usb_ep_enable(uvc->video.ep);
 
+		if (uvc->video.ep->desc)
+			uvcg_info(f,
+				"UVC ep config: speed=%u addr=0x%02x attrs=0x%02x maxpacket=%u maxburst=%u mult=%u wMaxPacket=0x%04x interval=%u\n",
+				f->config->cdev->gadget->speed,
+				uvc->video.ep->address,
+				uvc->video.ep->desc->bmAttributes,
+				uvc->video.ep->maxpacket, uvc->video.ep->maxburst,
+				uvc->video.ep->mult,
+				le16_to_cpu(uvc->video.ep->desc->wMaxPacketSize),
+				uvc->video.ep->desc->bInterval);
+		else
+			uvcg_err(f,
+				"UVC ep config: missing desc speed=%u maxpacket=%u maxburst=%u mult=%u\n",
+				f->config->cdev->gadget->speed,
+				uvc->video.ep->maxpacket, uvc->video.ep->maxburst,
+				uvc->video.ep->mult);
+
 		uvc->video.max_req_size = uvc->video.ep->maxpacket
 			* max_t(unsigned int, uvc->video.ep->maxburst, 1)
 			* (uvc->video.ep->mult);
 
+		uvcg_info(f,
+			"UVC max_req_size=%u (maxpacket=%u maxburst=%u mult=%u)\n",
+			uvc->video.max_req_size,
+			uvc->video.ep->maxpacket,
+			uvc->video.ep->maxburst,
+			uvc->video.ep->mult);
+
 		memset(&v4l2_event, 0, sizeof(v4l2_event));
 		v4l2_event.type = UVC_EVENT_STREAMON;
 		v4l2_event_queue(&uvc->vdev, &v4l2_event);