From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f174.google.com (mail-pg1-f174.google.com [209.85.215.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C7C9051A743 for ; Fri, 4 Sep 2026 18:20:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788546031; cv=none; b=MwhuQcVZ28WWsOsugiTk0I0D4ThN8uvXuzUjnKuM3UkY1cCh7erjoRdkYUron7I5u6vZDj7Z7sSUfWQ9L1SEuxHU/9D9C7IqcyDwxLEUs7hPvBt523ATXkXbnHipAKhdHk6cIG7lBJO5KZh0hTJ95i3ArmdfwNAGf/kmIq3SolQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788546031; c=relaxed/simple; bh=byKejZtAl6q7TXNAGPeYbR4LCvKQMlBWPXFv0oHjhEA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hAV2qcfyrcMm6AJq43GhWyOCz78OYkF3oeLpjGQM5gHXwUV/mt4a7vb1xi0awsL+pX0VN83lDFHnVLXsplu5uFW6Fe58xYIJANw9rohpgK4jhM1yrRPCBN5nrGGjmLCxCMPOGSudGy8ET0iEuLFGhFiIW60nYYjcoszjdjh+Iak= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=mC3WL4+W; arc=none smtp.client-ip=209.85.215.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mC3WL4+W" Received: by mail-pg1-f174.google.com with SMTP id 41be03b00d2f7-cc2276e6daeso1127577a12.0 for ; Fri, 04 Sep 2026 11:20:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1788546029; x=1789150829; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=byKejZtAl6q7TXNAGPeYbR4LCvKQMlBWPXFv0oHjhEA=; b=mC3WL4+WEbngGes0cuZkjNgSffbUd4hbsuivXCv2cxu4iL5dHXETt1uCkPWTIFD7YQ JtnYC9jDrcN0eOSP2NZdFRpbWtSD5U7bGm7lAoe3iNN349Bl8id3zcCQoxzFRsX8kr0t DSuNfUBZchNJzQSIWoPkc3HXI7r+suxEIcq7RZAnY5Kv3vGSytUcZx3vIzGu5KrAyNTs r1HqQXstoZGD3w271UG/ZzqG0IXVwiZmyuNcwDFZv8EZ+vpZd6LAdm38d3B/Msjxsdj2 3Jl481p9dhzEySxqbPEUywoajCtkDR2pcnoEpeQgR1HR/H+JjNCU+7XWCxqAdyfAeNjv 6L8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788546029; x=1789150829; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=byKejZtAl6q7TXNAGPeYbR4LCvKQMlBWPXFv0oHjhEA=; b=VTqzc2QtNwuv7C+IcHYPTey5D7+m/zVpcRRNS1czFnKp4zXqvUvTiOpLBgwHKXmf4z 62i71zyOeqt5uwnQORvDg3GHn11WfoXTc5kbKpzDVQuH/oTenGNT22XHXypa392OW4oy NVZLuIxB1a4LKnV6JZswnbJt/fpY7cTCqCfsjYz9qvh3IkAPw2e4/NO8ub5sFNaS62SB FbxNLZVNc7rsF43hKrByVQbJ4O+qfnm5a09paACnrND+keeq8Fe0Vtk2nQq4li4ODt0z bM4TIKaQLLGrq4/+PLXs/xqI2xNSrcHO1jJgNivnGmfviG0Bs1YXoE/mkzN0tFdS+2lm yBPQ== X-Gm-Message-State: AFuF++lFt2umj8CrCJqUpGC2veV7Uc4uyclYk2Sg/g3n+VWMToi18EtD yCwfTitmyGGRqAecrJRc4NY30/+DREQIOJVfGKbEX8Uk8ZCocdnqnWcTbEEx9mLpgVI= X-Gm-Gg: AYBFou3H79h3CK85Z1IoKJ6dMVADNGznGvUOX2RJchT6DBrYgr6zqm/cp3HHDGUWSRE bZQK5JdNETfHc28DCVRDM+EE+LwEvZXOEV8ylCGeFFbXnJsXbDfGDaxVWENOOOFMaovjUIaxWVP NZUATmKlJNo1VCpVC+j64OkVaJwBQPz/AoZ3zCnzKuGmeKBIuafTx8pegVC2uOf8UzwNeefHfyQ sM459sVdP+AhtMqCFjXe6iiEhc+PHHPVg3KWCDVE0J5y00HAyftDt/wTCYL1W+IKIvlk9r6b/d9 Aun4ryPuhPtBApjlxw+gy9QPAb4brfJ/9cFS9Ru4pHZnvW9DUl10Tb3fVwBlvqe+5QFPzEirmso OvGOvDXRnycBgRBWMjGt924ug4tqmShy0x/f4aABgOrKmo0rUIaCixWMkOb1LwBgItpOGwXZ0bz YNQ1ERLP6RdtIKM3CuueCSY6J6uBwORYPCyU9OmiCLYvj/8c5dRmCrR37KI9jhNdYrBVN6y6XEI w== X-Received: by 2002:a17:90a:d010:b0:38e:bbf1:de3f with SMTP id 98e67ed59e1d1-39b26272ef9mr13588885a91.12.1788546028788; Fri, 04 Sep 2026 11:20:28 -0700 (PDT) Received: from localhost.localdomain ([2001:1960:1401:126c:876e:d154:517e:4c6f]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-3342af0bc08sm6350509eec.17.2026.09.04.11.20.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Sep 2026 11:20:28 -0700 (PDT) From: Hanh Kieu To: geraldogabriel@gmail.com, perex@perex.cz, tiwai@suse.com Cc: linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ALSA: usb-audio: add Pioneer DJ DDJ-SZ support Date: Fri, 4 Sep 2026 11:20:23 -0700 Message-ID: <20260904182023.4486-1-hhkieu@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Geraldo Nascimento wrote: > Are you sure is_pioneer_implicit_fb() isn't returning false and you're > picking up on a generic sync ep instead? > > You should double-check that function is returning true or false because > it will return false when USB_ENDPOINT_USAGE_IMPLICIT_FB isn't > set on bmAttributes of a Isochronous IN EP. Good catch, thanks -- I checked against the real device rather than assuming. lsusb -v on the DDJ-SZ shows both endpoints (0x01 OUT, 0x82 IN) as Isochronous / Asynchronous with Usage Type = Data (bmAttributes = 0x05). is_pioneer_implicit_fb() accepts the capture endpoint's usage being either USB_ENDPOINT_USAGE_DATA or USB_ENDPOINT_USAGE_IMPLICIT_FB, not IMPLICIT_FB exclusively, so Data usage does pass that check. I also traced snd_usb_parse_implicit_fb_quirk()'s dispatch order for this device to make sure nothing generic intercepts first: no fixed or capture quirk-table entry matches 08e4:0191, it isn't UAC2 (bInterfaceClass is vendor-spec, not USB_CLASS_AUDIO), and it isn't the Roland vendor ID. So is_pioneer_implicit_fb() is the function actually being reached and returning true for this device, not a coincidental generic fallback. Happy to add a comment near the quirk-table entry noting the real bmAttributes value if that would help future readers. Thanks, Hanh Kieu