From 2fa996ed616232912dfa4c6dee825a1d84b8ff8a Mon Sep 17 00:00:00 2001
From: Brad Stein <Brad.Stein@gmail.com>
Date: Mon, 26 Jan 2026 20:58:48 -0300
Subject: [PATCH] kernel: log uvc ep sizing

---
 scripts/kernel/uvc-debug.patch | 62 ++++++++++++++++++++++++++++++++--
 1 file changed, 59 insertions(+), 3 deletions(-)

diff --git a/scripts/kernel/uvc-debug.patch b/scripts/kernel/uvc-debug.patch
index bf5ffb5..a438aa0 100644
--- a/scripts/kernel/uvc-debug.patch
+++ b/scripts/kernel/uvc-debug.patch
@@ -1,6 +1,6 @@
 --- a/drivers/usb/gadget/function/uvc_video.c
 +++ b/drivers/usb/gadget/function/uvc_video.c
-@@ -503,6 +503,10 @@
+@@ -503,9 +503,17 @@
  	unsigned int max_req_size, req_size, header_size;
  	unsigned int nreq;
  
@@ -11,7 +11,14 @@
  	max_req_size = video->max_req_size;
  
  	if (!usb_endpoint_xfer_isoc(video->ep->desc)) {
-@@ -534,6 +538,16 @@
++		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 +542,16 @@
  	}
  	video->req_size = req_size;
  
@@ -28,7 +35,19 @@
  	/* 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
-@@ -764,20 +778,70 @@
+@@ -558,6 +576,11 @@
+ 	 */
+ 	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 +787,70 @@
  {
  	int ret;
  
@@ -99,3 +118,40 @@
  	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
+@@ -362,10 +362,34 @@
+ 			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);