From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-170.mta1.migadu.com (out-170.mta1.migadu.com [95.215.58.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8388E2777F7 for ; Tue, 22 Apr 2025 11:54:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745322894; cv=none; b=kF/tKJncWBiP2Ksp75idIHjKZ1fMnrG64ulSz9o8vQjQzkr+pBPiOkEFm89AMzFZniEDMlcKtOhLLoPmcBm8m7z9d3XPKnBpN/zPsvQpoNUDu6c1jgjMqSoO0S7qgd8azoPPskfMXy+9sseVqNo+9Exd0PWd9XlnzU3cbUK76Ck= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745322894; c=relaxed/simple; bh=OGWPYYpm06/Vuuw2dz5HhiOYfy9LMdq+m0xpWdPvevs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sye6d8GgJkyobSsZVaec3p2SM4+eJbPhzHo/dL7Q9gWzoHYK4zo8YXXc4WKXVk/hl+qRx9OYNH8iHDB/HLrEzPK9LnTD3C1ZzbCddY5FaQ92VDKWO1dfLzT2KPMStjpoodYYs6etz3fJizO3osNxngWAPvJ6bCAqnNggI8Kzn2Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=LbXxO/e+; arc=none smtp.client-ip=95.215.58.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="LbXxO/e+" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745322890; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OGWPYYpm06/Vuuw2dz5HhiOYfy9LMdq+m0xpWdPvevs=; b=LbXxO/e+Ep7PYf8RyBFjY/FGTQ5z/S6BrkyOVdJS99H2bSpST1gsdwR8+9boQrU01lUvvP 159okSYI19pjsS8ai58lTvJC4DZx7B2UEVVZ97dG3IOklIuaxVngALSPwxQHH/qJ76HaNq aYmBbcttqQ5uLDWvSmpURBkYLuSNzW8= Date: Tue, 22 Apr 2025 13:28:06 +0200 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [RFC 00/15] ALSA/ASoC: USB Audio Offload To: Cezary Rojewski , Takashi Iwai Cc: broonie@kernel.org, tiwai@suse.com, perex@perex.cz, amadeuszx.slawinski@linux.intel.com, linux-sound@vger.kernel.org, gregkh@linuxfoundation.org, quic_wcheng@quicinc.com, mathias.nyman@linux.intel.com References: <20250409110731.3752332-1-cezary.rojewski@intel.com> <87v7rcwbyn.wl-tiwai@suse.de> <8e3fd738-c2c3-4ea0-963e-477c2fb253b6@intel.com> <87sem9xuxs.wl-tiwai@suse.de> <5f3c62e3-6993-4595-80fc-eb77c0c11f1d@intel.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Pierre-Louis Bossart In-Reply-To: <5f3c62e3-6993-4595-80fc-eb77c0c11f1d@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT > In regard to the HDAudio point, I see clear benefits by having HDAudio and USB aligned in the approach on ASoC side. It's a path that's known, works and is well tested. The current direction for HDaudio is to have the DSP handle ALL streams with DSP-enabled drivers (or none with snd-hda-intel). But for USB we absolutely need the ability to bypass the DSP when the resources are exceeded (too many endpoints, too many channels, etc), or when low-latency is required (lowering CPU utilization comes at the expense of latency). In other words, the USB solution MUST expose two PCM paths, a legacy one and a DSP-one, and a sideband communication between DSP and legacy drivers to manage resources. HDAudio has none of those concepts, which makes it hard to see what the suggested alignment is?