From patchwork Sun May 29 22:38:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Grzeschik X-Patchwork-Id: 577186 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EA80C4332F for ; Sun, 29 May 2022 22:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231285AbiE2WjB (ORCPT ); Sun, 29 May 2022 18:39:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231297AbiE2Wi5 (ORCPT ); Sun, 29 May 2022 18:38:57 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F18D45A15C for ; Sun, 29 May 2022 15:38:55 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nvRYj-0001Q2-Ad; Mon, 30 May 2022 00:38:53 +0200 Received: from [2a0a:edc0:0:1101:1d::ac] (helo=dude04.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1nvRYi-005L6W-Uq; Mon, 30 May 2022 00:38:51 +0200 Received: from mgr by dude04.red.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1nvRYg-000Rcp-Fs; Mon, 30 May 2022 00:38:50 +0200 From: Michael Grzeschik To: linux-usb@vger.kernel.org Cc: balbi@kernel.org, paul.elder@ideasonboard.com, kieran.bingham@ideasonboard.com, nicolas@ndufresne.ca, laurent.pinchart@ideasonboard.com, kernel@pengutronix.de Subject: [PATCH v2 1/3] usb: gadget: uvc: calculate the number of request depending on framesize Date: Mon, 30 May 2022 00:38:46 +0200 Message-Id: <20220529223848.105914-2-m.grzeschik@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220529223848.105914-1-m.grzeschik@pengutronix.de> References: <20220529223848.105914-1-m.grzeschik@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: mgr@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-usb@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org 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) Signed-off-by: Michael Grzeschik --- v1 -> v2: - using clamp instead of min/max - added calculation example to description - commented the additional division by two in the code 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 d25edc3d2174e1..eb9bd9d32cd056 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; }