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 EE8A835206F; Tue, 26 Aug 2025 14:42:36 +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=1756219357; cv=none; b=mYuuNbpD1knXz1fVkKysakV3zs7xlyAFOGcTcgcXIWyvI7W1zL+FPitIPb4zl0qgjLc6SWBs7YZRde15MfjQ6c+vDOVhnFUUS7sBTVpssLCcjAfYBVBOuBB8V290M8GVMuHkJV8OpkqOTxM/+VATPMYA7YeSlRpblvNCAxnRJeE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756219357; c=relaxed/simple; bh=fvHOm1T5WuVoJ8QC02yqFzZlctIuTzFUi4E80qgHJTg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nR1vVCPYsieA4mNj+5oMiGhfqVau4iXC3x0odMOagIoKUhaf8bSuVk8/vdlQ+yT9vg0e6CR8V+lq5p/jcj9Kl4uZ/exxxXcGT1aVnD0PN5gZVJuxNadguz1SxsCD6hO2GsYyrKIXtcUU1Gt4CLYrU4Md8OLSzpJPz/WjfY5VAUs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=z++FVuaU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="z++FVuaU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8265FC4CEF1; Tue, 26 Aug 2025 14:42:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756219356; bh=fvHOm1T5WuVoJ8QC02yqFzZlctIuTzFUi4E80qgHJTg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=z++FVuaUlca06o2TUQtZdBLPV37DIwucyuois3J1jnqCnI4k3ccSUxuaSpjw0dvvR n7bf2s7X0JigLpFSfWuQJpLJW96acSlI7BKbc7zx21Ntl6ELO1P91XNnDdGxiMvyvh EgjZdyeYMdgwBFsgPJSslzJC/wn3qJhFzNE1el/k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Geoffrey D. Bennett" , Takashi Iwai , Sasha Levin Subject: [PATCH 5.4 349/403] ALSA: scarlett2: Add retry on -EPROTO from scarlett2_usb_tx() Date: Tue, 26 Aug 2025 13:11:15 +0200 Message-ID: <20250826110916.517725604@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110905.607690791@linuxfoundation.org> References: <20250826110905.607690791@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ 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 around snd_usb_ctl_msg() instead of scarlett2_usb_tx() ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- sound/usb/mixer_scarlett_gen2.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/sound/usb/mixer_scarlett_gen2.c +++ b/sound/usb/mixer_scarlett_gen2.c @@ -118,6 +118,8 @@ #define SCARLETT2_MIXER_MAX_VALUE \ ((SCARLETT2_MIXER_MAX_DB - SCARLETT2_MIXER_MIN_DB) * 2) +#include + /* map from (dB + 80) * 2 to mixer value * for dB in 0 .. 172: int(8192 * pow(10, ((dB - 160) / 2 / 20))) */ @@ -591,6 +593,8 @@ 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 +618,7 @@ 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 +629,10 @@ 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",