From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A273F286D62 for ; Wed, 13 Aug 2025 15:55:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755100555; cv=none; b=snWgBNzIKD+zGHdVa+Lu9mTscFgAoFw1d3JA9qvH5P2MNSNiON+L93R2llzuZgl+O4P112sETPlZ25H0F1tpzyHlBqjRX1WcUIo6NQiSsZifixe1fXvynvEfAOVm4CpIpy9CGkqthYwqPrYowp+Ffruz/sgIxWxksMAVtpLnn0c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755100555; c=relaxed/simple; bh=zYTLanYT1OsG/PIur8uERAqhnN6cIvHBsGTUDepi0Y8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FsJbLf6AOvrNVDgSPDZ95AuSwrvMN2XdSp6E9JaRzkxokpOtdhy4+zrG2rsGp9QCx89pb1/zQVXRZQ/gLLV6v+sxHYgUBDevCxF/n19risCyHy/nWV4atSH179XEEckqd5k/jVL4sxFS55GJZ6G3YzjXstEZylQ2PK5S8aGWtyM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j09Fl+cK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="j09Fl+cK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2C8EC4CEEB; Wed, 13 Aug 2025 15:55:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755100554; bh=zYTLanYT1OsG/PIur8uERAqhnN6cIvHBsGTUDepi0Y8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j09Fl+cKdI875zybFb1l9D7jS821WJYYG41JiiGzc0+TGI/yNJrwVhBEJTE/Q7oNI lvYPs4+VfI3jK9+I9/gyAoTcxRYGbtFpDTeQxdkVpUARG75NtzxKYiLoP//WjsYlXX CoChLizLors0F0+Q0+6IsG9GH704lLAAgtGLKe6iIWdZP3aiSuQjXzUO1/efd1PSWA Wf96mzgk9ZDXprxu6EEOuGsYQNCqOxmfUQwPV/j6z2Q1pyHw1hZ8uBgrJNieTm07YO cfU8kG7yM71iifwI5a85h4/QbhOi/Yu2ccYyFFGMOdcYk/WlMhDr4VMn9Mnt/o3Opd gXRah7cnPdAdw== From: Sasha Levin To: stable@vger.kernel.org Cc: "Geoffrey D. Bennett" , Takashi Iwai , Sasha Levin Subject: [PATCH 5.10.y] ALSA: scarlett2: Add retry on -EPROTO from scarlett2_usb_tx() Date: Wed, 13 Aug 2025 11:55:06 -0400 Message-Id: <20250813155506.2051597-1-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <2025081244-epileptic-value-7d4e@gregkh> References: <2025081244-epileptic-value-7d4e@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Geoffrey D. Bennett" [ Upstream commit 8a15ca0ca51399b652b1bbb23b590b220cf03d62 ] During communication with Focusrite Scarlett Gen 2/3/4 USB audio interfaces, -EPROTO is sometimes returned from scarlett2_usb_tx(), snd_usb_ctl_msg() which can cause initialisation and control operations to fail intermittently. This patch adds up to 5 retries in scarlett2_usb(), with a delay starting at 5ms and doubling each time. This follows the same approach as the fix for usb_set_interface() in endpoint.c (commit f406005e162b ("ALSA: usb-audio: Add retry on -EPROTO from usb_set_interface()")), which resolved similar -EPROTO issues during device initialisation, and is the same approach as in fcp.c:fcp_usb(). Fixes: 9e4d5c1be21f ("ALSA: usb-audio: Scarlett Gen 2 mixer interface") Closes: https://github.com/geoffreybennett/linux-fcp/issues/41 Cc: stable@vger.kernel.org Signed-off-by: Geoffrey D. Bennett Link: https://patch.msgid.link/aIdDO6ld50WQwNim@m.b4.vu Signed-off-by: Takashi Iwai [ Applied retry logic directly in scarlett2_usb() instead of scarlett2_usb_tx() ] Signed-off-by: Sasha Levin --- sound/usb/mixer_scarlett_gen2.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c index 1b7c7b754c38..1c31a9d21d42 100644 --- a/sound/usb/mixer_scarlett_gen2.c +++ b/sound/usb/mixer_scarlett_gen2.c @@ -95,6 +95,7 @@ #include #include #include +#include #include #include @@ -591,6 +592,8 @@ static int scarlett2_usb( u16 req_buf_size = sizeof(struct scarlett2_usb_packet) + req_size; u16 resp_buf_size = sizeof(struct scarlett2_usb_packet) + resp_size; struct scarlett2_usb_packet *req = NULL, *resp = NULL; + int retries = 0; + const int max_retries = 5; int err = 0; req = kmalloc(req_buf_size, GFP_KERNEL); @@ -614,6 +617,7 @@ static int scarlett2_usb( if (req_size) memcpy(req->data, req_data, req_size); +retry: err = snd_usb_ctl_msg(mixer->chip->dev, usb_sndctrlpipe(mixer->chip->dev, 0), SCARLETT2_USB_VENDOR_SPECIFIC_CMD_REQ, @@ -624,6 +628,10 @@ static int scarlett2_usb( req_buf_size); if (err != req_buf_size) { + if (err == -EPROTO && ++retries <= max_retries) { + msleep(5 * (1 << (retries - 1))); + goto retry; + } usb_audio_err( mixer->chip, "Scarlett Gen 2 USB request result cmd %x was %d\n", -- 2.39.5