From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 3E1EF85620; Wed, 8 May 2024 13:16:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715174175; cv=none; b=Uq5fHTNuicrzplht502FWzbq3C0ymeChZOT6XbKoVn2idKWhRnP8vAaoO+w9OKo3GXDvdHBMNOEfT1kuNkkf8quWmDjj6GyEBMzDI5L8GB4ws/QyU3peTX5XJwOyaHN6XumD0GhDM63tNZi14p//d1IlVBknBZPvV043f9CxyWQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715174175; c=relaxed/simple; bh=XNeckRnANZcfLQNUQ8Z5GX84AOZZtK3YH+F5AxvIfmQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RQFsB6EgnQji56Zv8m+B21iIDQhFJhjGpqbFT1/l+KDIK8EkYm8Y1mFE39je2rabk2zf2/69AR3qAe0ZN2W3cdobjwt2VyhYzgA9ZXLb5EOH/GY2vTx6j2PSnt2su9w1hVs2t3tjGPN19yor9a5VgdGzTZgUDlP4Gozw+OvONVc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=iDvvLr21; arc=none smtp.client-ip=192.198.163.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="iDvvLr21" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1715174174; x=1746710174; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=XNeckRnANZcfLQNUQ8Z5GX84AOZZtK3YH+F5AxvIfmQ=; b=iDvvLr21cD0nDvGDK7Ccpx5EDkAZ0y0gJK8zkxhicsiUZLvNWWKJZqOg oB4NKz+TlvOsOj9zK9XHEJ9EjmNSfoEuxagZ74czcuqUnkdr4W27QE34z 1vLmSrLIj6iA+jBed7pKFe2/vcNsNR4mdXz3pTOdH55v/7nIgxrgC3xQ6 FIKwkD8H6oxZeI0XB89vzMFbe6LK2soyNLc/TPiluJmjt7X/fjVUTzewv PVEL0niU/IALXjPJtYWeAB+vFDscxskkQeRLEbDXYVOktmZv6ZpveyiXo LD2xG2s2LhF9GuFtZZuzqEoziaLMp9Rz5/epnNSkJqHOUCxrFRM0NOSzw Q==; X-CSE-ConnectionGUID: vH4wXSX0SnytZMSfExtWlA== X-CSE-MsgGUID: MKIfV/w4T96zPh6uQQfpPg== X-IronPort-AV: E=McAfee;i="6600,9927,11066"; a="36413239" X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="36413239" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:16:13 -0700 X-CSE-ConnectionGUID: k1L20U8iT+SrjOlDKwEB5A== X-CSE-MsgGUID: hl5X9CpDQOm8ex+CqCP06g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="33356774" Received: from sskolar-mobl.amr.corp.intel.com (HELO [10.212.67.115]) ([10.212.67.115]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:16:12 -0700 Message-ID: <1e98935e-e35a-49e0-bbbf-ff326d40b581@linux.intel.com> Date: Tue, 7 May 2024 16:20:26 -0500 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v21 22/39] ALSA: usb-audio: Prevent starting of audio stream if in use To: Wesley Cheng , srinivas.kandagatla@linaro.org, mathias.nyman@intel.com, perex@perex.cz, conor+dt@kernel.org, corbet@lwn.net, lgirdwood@gmail.com, andersson@kernel.org, krzk+dt@kernel.org, gregkh@linuxfoundation.org, Thinh.Nguyen@synopsys.com, broonie@kernel.org, bgoswami@quicinc.com, tiwai@suse.com, bagasdotme@gmail.com, robh@kernel.org, konrad.dybcio@linaro.org Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-sound@vger.kernel.org, linux-usb@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-doc@vger.kernel.org, alsa-devel@alsa-project.org References: <20240507195116.9464-1-quic_wcheng@quicinc.com> <20240507195116.9464-23-quic_wcheng@quicinc.com> Content-Language: en-US From: Pierre-Louis Bossart In-Reply-To: <20240507195116.9464-23-quic_wcheng@quicinc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit > If a PCM device is already in use, the check will return an error to > userspace notifying that the stream is currently busy. This ensures that > only one path is using the USB substream. What was the point of having a "USB Mixer" then?