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=-8.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C4F33C2D0A3 for ; Mon, 9 Nov 2020 08:29:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FA3F20E65 for ; Mon, 9 Nov 2020 08:29:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ivitera.com header.i=@ivitera.com header.b="QK965PRV"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ivitera.com header.i=@ivitera.com header.b="l6P/zTnZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729236AbgKII3d (ORCPT ); Mon, 9 Nov 2020 03:29:33 -0500 Received: from cable.insite.cz ([84.242.75.189]:53648 "EHLO cable.insite.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbgKII3d (ORCPT ); Mon, 9 Nov 2020 03:29:33 -0500 X-Greylist: delayed 312 seconds by postgrey-1.27 at vger.kernel.org; Mon, 09 Nov 2020 03:29:32 EST Received: from localhost (localhost [127.0.0.1]) by cable.insite.cz (Postfix) with ESMTP id 0A5BCA93253BA; Mon, 9 Nov 2020 09:24:17 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=ivitera.com; s=mail; t=1604910257; bh=GFxrZmOjHf1coQIZ1tOskOK/f3baZkB6oWTLPzXpIoY=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=QK965PRVN184B0sSUibHV8LDjeZP1b6YeVUWkE+vPMzR6Nw1ea0+BvqoUbM1dVlvk TZxi5t/UoTE/pPAemRcRmufhbOkkfWyQEX2NEvPzvqGAsM7JKCjlfBlxzqL7+7E4/x c0luAoi5TDzVdhxG/SPV9PJnIBwm1Y9LHsxHm9PA= Received: from cable.insite.cz ([84.242.75.189]) by localhost (server.insite.cz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bDuFcrYv9yJ3; Mon, 9 Nov 2020 09:24:11 +0100 (CET) Received: from [192.168.105.22] (ip28.insite.cz [81.0.237.28]) (Authenticated sender: pavel) by cable.insite.cz (Postfix) with ESMTPSA id 7790AA93158DC; Mon, 9 Nov 2020 09:24:11 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=ivitera.com; s=mail; t=1604910251; bh=GFxrZmOjHf1coQIZ1tOskOK/f3baZkB6oWTLPzXpIoY=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=l6P/zTnZu7xLX3vRtuzZnvQis65mA+6RXJsccfWKwyZODGmO+BR9yhV1e1iZdSaxb ckaUe8KOZR0DFu+mlnPuX5sAPdZrXoasZ4WhZtOQKKREa6th2adeOUzAOcSpRkOoIJ 2TCCWt6bX3z80NoZ6U1y4tKl5Fi0DQvePR4mvyvw= Subject: Re: [PATCH 3/3] usb: gadget: u_audio: add real feedback implementation To: Ruslan Bilovol , balbi@kernel.org Cc: linux-usb@vger.kernel.org, gschmottlach@gmail.com References: <1604794711-8661-1-git-send-email-ruslan.bilovol@gmail.com> <1604794711-8661-4-git-send-email-ruslan.bilovol@gmail.com> From: Pavel Hofman Message-ID: Date: Mon, 9 Nov 2020 09:24:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1604794711-8661-4-git-send-email-ruslan.bilovol@gmail.com> Content-Type: text/plain; charset=iso-8859-2 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hi Bilovol, Dne 08. 11. 20 v 1:18 Ruslan Bilovol napsal(a): > This adds interface between userspace and feedback > endpoint to report real feedback frequency to the Host. > > Current implementation adds new userspace interface > ALSA mixer control "PCM Feedback Frequency Hz" (similar > to aloop driver's "PCM Rate Shift 100000" mixer control) > > We allow +/-20% deviation of nominal sampling frequency, > that usually is more than enough in real-world usecases > > Usage of this new control is easy to implement in > existing userspace tools like alsaloop from alsa-utils. > > Signed-off-by: Ruslan Bilovol > --- > drivers/usb/gadget/function/f_uac2.c | 4 ++ > drivers/usb/gadget/function/u_audio.c | 93 +++++++++++++++++++++++++++++++++++ > drivers/usb/gadget/function/u_audio.h | 7 +++ > 3 files changed, 104 insertions(+) Thanks a lot for the great implementation. IIUC the control element sets integer frequency in Hz. Often the clocks deviate by small fractions of Hz. Please have you considered the value to be e.g. in 100th of Hz for finer control of the samplerate? Similar to the PCM Rate Shift which has a step 100000th of the samplerate. Thanks a lot. Best regards, Pavel.