From c2d17078980a3814ba7c502eb29e1839b9b63e45 Mon Sep 17 00:00:00 2001 From: Michael Grzeschik Date: Mon, 30 May 2022 00:38:46 +0200 Subject: [PATCH] usb: gadget: uvc: calculate the number of request depending on framesize [ Upstream commit 87d76b5f1d8eeb49efa16e2018e188864cbb9401 ] The current limitation of possible number of requests being handled is dependent on the gadget speed. It makes more sense to depend on the typical frame size when calculating the number of requests. This patch is changing this and is using the previous limits as boundaries for reasonable minimum and maximum number of requests. For a 1080p jpeg encoded video stream with a maximum imagesize of e.g. 800kB with a maxburst of 8 and an multiplier of 1 the resulting number of requests is calculated to 49. 800768 1 nreqs = ------ * -------------- ~= 49 2 (1024 * 8 * 1) Tested-by: Dan Vacura Signed-off-by: Michael Grzeschik Link: https://lore.kernel.org/r/20220529223848.105914-2-m.grzeschik@pengutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/uvc_queue.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c index 951934aa44541..ec500ee499eed 100644 --- a/drivers/usb/gadget/function/uvc_queue.c +++ b/drivers/usb/gadget/function/uvc_queue.c @@ -44,7 +44,8 @@ static int uvc_queue_setup(struct vb2_queue *vq, { struct uvc_video_queue *queue = vb2_get_drv_priv(vq); struct uvc_video *video = container_of(queue, struct uvc_video, queue); - struct usb_composite_dev *cdev = video->uvc->func.config->cdev; + unsigned int req_size; + unsigned int nreq; if (*nbuffers > UVC_MAX_VIDEO_BUFFERS) *nbuffers = UVC_MAX_VIDEO_BUFFERS; @@ -53,10 +54,16 @@ static int uvc_queue_setup(struct vb2_queue *vq, sizes[0] = video->imagesize; - if (cdev->gadget->speed < USB_SPEED_SUPER) - video->uvc_num_requests = 4; - else - video->uvc_num_requests = 64; + req_size = video->ep->maxpacket + * max_t(unsigned int, video->ep->maxburst, 1) + * (video->ep->mult); + + /* We divide by two, to increase the chance to run + * into fewer requests for smaller framesizes. + */ + nreq = DIV_ROUND_UP(DIV_ROUND_UP(sizes[0], 2), req_size); + nreq = clamp(nreq, 4U, 64U); + video->uvc_num_requests = nreq; return 0; }