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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7949CC4167B for ; Tue, 27 Dec 2022 14:02:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229762AbiL0OCg (ORCPT ); Tue, 27 Dec 2022 09:02:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229521AbiL0OCf (ORCPT ); Tue, 27 Dec 2022 09:02:35 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44AB92719; Tue, 27 Dec 2022 06:02:34 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 624DA21A14; Tue, 27 Dec 2022 14:02:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1672149752; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0KLiBDtIA7sN+ETgDOxVP3hBKlixZxiuD/45RsLx3hE=; b=vUr3dlNES5rrO/KcZ06D38wB0Lk2NfSAB9F0/HFo4qT1AngDH194kUNc/FFdC+nBz2shYu at9RsZ8jXUf+UOyvOuI0IJtC8qWdRmBH1jHIZqYqNuxVDDMltj8jwVNPhhlq2YtoVW/0YT GLB5Yqvw2YQu7TvMFzDL1ZOPbl79tMA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1672149752; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0KLiBDtIA7sN+ETgDOxVP3hBKlixZxiuD/45RsLx3hE=; b=Ih06188sb6XgugJG7XDgDd4abpGli3pOSvNztn0TlNE+g7qC7rlc4fjenD08gjlhDre0u4 ZWte3co7ov6SIaAw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id DC02613913; Tue, 27 Dec 2022 14:02:31 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id hC/nNPf6qmOLZwAAMHmgww (envelope-from ); Tue, 27 Dec 2022 14:02:31 +0000 Date: Tue, 27 Dec 2022 15:02:31 +0100 Message-ID: <87r0wl0wso.wl-tiwai@suse.de> From: Takashi Iwai To: Greg KH Cc: Mark Brown , Wesley Cheng , srinivas.kandagatla@linaro.org, mathias.nyman@intel.com, perex@perex.cz, lgirdwood@gmail.com, andersson@kernel.org, krzysztof.kozlowski+dt@linaro.org, Thinh.Nguyen@synopsys.com, bgoswami@quicinc.com, tiwai@suse.com, robh+dt@kernel.org, agross@kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-usb@vger.kernel.org, quic_jackp@quicinc.com, quic_plai@quicinc.com Subject: Re: [RFC PATCH 03/14] ASoC: qcom: Add USB backend ASoC driver for Q6 In-Reply-To: References: <20221223233200.26089-1-quic_wcheng@quicinc.com> <20221223233200.26089-4-quic_wcheng@quicinc.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Tue, 27 Dec 2022 14:45:13 +0100, Greg KH wrote: > > On Tue, Dec 27, 2022 at 01:04:55PM +0000, Mark Brown wrote: > > On Sat, Dec 24, 2022 at 10:02:59AM +0100, Greg KH wrote: > > > On Fri, Dec 23, 2022 at 03:31:49PM -0800, Wesley Cheng wrote: > > > > > > + * struct q6usb_offload > > > > + * @dev - dev handle to usb be > > > > > "be"? What is that? > > > > Back end. This is a concept in DPCM which should be reasonably > > discoverable to people working on the audio portions of this code. > > Ok, then how is the reference counting logic handled here? USB devices > can be removed from the system at any point in time... The whole picture is fairly complex, and this patch is a part belonging to the ASoC machine driver -- that is, it's bound to the Qualcomm host, and there can be only one on a system. OTOH, USB audio devices are still managed by the existing USB audio driver as is, and they can be multiple and any devices. The basic idea here is a hijack of the USB data processing in USB audio driver with the offloading mechanism by this ASoC driver (only if the condition met). thanks, Takashi