From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8EAFC352A3 for ; Tue, 11 Feb 2020 16:10:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99C412070A for ; Tue, 11 Feb 2020 16:10:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UVOKTCHw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730781AbgBKQKg (ORCPT ); Tue, 11 Feb 2020 11:10:36 -0500 Received: from mail-oi1-f195.google.com ([209.85.167.195]:38403 "EHLO mail-oi1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730005AbgBKQKf (ORCPT ); Tue, 11 Feb 2020 11:10:35 -0500 Received: by mail-oi1-f195.google.com with SMTP id l9so13269374oii.5 for ; Tue, 11 Feb 2020 08:10:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=xvPGrxFUGqMLSAiWfimrK4h2s+k8AyjaVs9/AW/hgW8=; b=UVOKTCHw1M6fbeb5+iIybMSi1mpRpN4EIktFFwL2Rmkj28+pPcdBcN5LXnTAyok1aK I1z2D4JpLfOZScrHtTm1grPhnaZYXNP2fPjzEoDhqOgXuT/En0LusO5UsMqTw5BLNF3M hcl2+0hyt1GZjhZ+iCGdUa02CuTFuJn9tmeHk0nXw9QgPMG6EZVVyeiboy1Aicgn05Ot v4gi/ViJZmjlAKaK7ulFiHa8pU2kneI8ZaE90FTCPOAMLWJQuxeVv0pV/LK3baErc3HF ZpDRXq2t75N6qEE0oxRT8K7CTqJG/uinvbRSLhe8rrfTSZWZWoJxL2J+WC1U4/1KRiXf 1iUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=xvPGrxFUGqMLSAiWfimrK4h2s+k8AyjaVs9/AW/hgW8=; b=ICt+0wqu2yD+1DamHaZUsaJHajC2j+w1sdN5i1iZ7uLzvw2MKOUH0zmZCcNfxX0N+H v6PVNEH670V4GmIgFfthYpoZrjGBxLo+pbpOSVN5YH+Q9wJAhmVjqmUlfUt4bKrFMO3w txocT80AtJ2AarAOOnWccmrKOpeGM67B88Mizj70Rtk916Q0pbZLjD0uGluDMt/UKnzd Mmip1JszquTjCT/eRAoviNp8xO25XYjOzBYYw4391T+BKGO83ay21BoU4KfZ/G6JnvAr lN7XO5GtNEzTtTgFMNq6j1/0QPVbTtme8G4hskl0F+ghV1CEdEXF4EnHUj6+eYC4Ng+Q hgnQ== X-Gm-Message-State: APjAAAXt1GeLxiC2MrCfYR6T9U9oz691UwKVQRJVXCUqQB9RPce8t0H6 YaYn64avPB0ccNF6Y2RgwTWhBR+6sTc3UoSLX2BFvMxhj3A= X-Google-Smtp-Source: APXvYqwdYHW3b9A/kYLaGeypbGhchdIOgNML7kUSPRdj/JL9DSEpXWCndq6GIg4AowyzeDZF3TArXt8kJnIloI71ZxE= X-Received: by 2002:aca:50cd:: with SMTP id e196mr3332127oib.178.1581437434605; Tue, 11 Feb 2020 08:10:34 -0800 (PST) MIME-Version: 1.0 References: <4bd36708-0ade-fbd7-5eec-5b8df7b3f2ee@ivitera.com> In-Reply-To: <4bd36708-0ade-fbd7-5eec-5b8df7b3f2ee@ivitera.com> From: Ruslan Bilovol Date: Tue, 11 Feb 2020 18:10:23 +0200 Message-ID: Subject: Re: usb:gadget:f_uac2: EP OUT is adaptive instead of async To: Pavel Hofman Cc: linux-usb@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, Feb 6, 2020 at 3:35 PM Pavel Hofman wrote: > > Hi, > > The existing UAC2 implementation presents itself as asynchronous > USB_ENDPOINT_SYNC_ASYNC > https://github.com/torvalds/linux/blob/master/drivers/usb/gadget/function/f_uac2.c#L276 > + > https://github.com/torvalds/linux/blob/master/drivers/usb/gadget/function/f_uac2.c#L285 > . > > However: > 1) The function does not define any feedback endpoint > > 2) IMO in reality it is adaptive - the g_audio capture device accepts > any data passed by the USB host, the USB host is the one which defines > the data pace. > > While Linux and reportedly OSX accept the async EP OUT without explicit > feedback EP IN, Windows does not. > > Simply changing USB_ENDPOINT_SYNC_ASYNC to USB_ENDPOINT_SYNC_ADAPTIVE > for the FS and HS output endpoints fixes the windows problem and IMO > corrects the config to reflect real function. > > There are multiple projects underway adding the async feedback EP, but > in the meantime I think the .bmAttributes information should be changed > as above, making the device usable in Windows for everyone. Are you working on async feedback EP implementation? I'm interested in that feature and I can implement it soon but do not want to do double work if somebody is already working on it and will send to the community soon Thanks, Ruslan > > Thanks a lot for considering. > > Best regards, > > Pavel.