From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793627262; b=wxjysTNSB4M/JGD1OZg76E24cRbldl2C5eOBZLxn59nJ1rm5Inl0QnAIHG7Fts2yTLos DlOQypRG+2b+GF3Rt6Rrxoy6orFToFmVbowwz/sZFvg1RS+8G+xS1tdGj15Xp/XcFDa2F A6V/SO+OwL1lxMwzfw6OcCdHk2EwjY9rqdmmmXp0G3Bn3u2aoyYpDKhHXPQ0UplVSr0ag ux8xZR1nVlrpj+UlzCVkXnhmricqYr0KoW8yvlLLo0uM8IUmZXSZmVc0ZmvrbbS5itmUf 55cdjD8wH89hTALtJlmT6lcsZ5nc6zcdXDDLFd3LYk22kaAeJKAY64dstgeytD9z9CQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793627262; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=dKnMPTxu6C3c9imeKsgoo/aeMUZcg0YAXsEX71shqBk=; b=j0yV3cb7TbRc97o2zNftVRBVqG4oauFMtkSvY5P3Lk2Aal6IxisJlzgnjzT4zVjnLVzF fPspSj+Nwb7bZpChVC0RfTk7S0uvpY8HD4e1zj9Z6PB0f8OVOLsEtoYmqdn1XCeAib41k m7Ngo6jZLl8LcklzrTsirCg2fCwxDCYwFNN8iw9tp/NLH6g2Kd2iX4Zi0929uSJ9Y50ds CwyzojND9WoMXTkdxfE9J2dmx6+N858P2+MW2lTBG2YvavH6mXYvrkwY00Il9V2IvWvt2 0SSUSW5jaOwwdhfADoGEstOk6Z1oETwpeUzxOt2Jsc/cz/JP6sPtiZmMfQ4qcA2yDDg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="BS3nx/aK"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B79BF606A333 for ; Mon, 2 Nov 2026 13:47:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=BS3nx/aK Received: by smtp.kernel.org (Postfix) with ESMTPSA id 47F7A1F00A1A; Mon, 2 Nov 2026 13:47:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793627261; bh=dKnMPTxu6C3c9imeKsgoo/aeMUZcg0YAXsEX71shqBk=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=BS3nx/aKj8P+zdBXL9uWidZe5p7vM1z4vi2g5/etxL5N/8Tpl327yfUQPAJEeJx6V xHVGxHORgkVtk2DRTskie9n1SDgdgAygX+HbvKA3kErNcw4T41ByXppypbHs1w/fNq TflXsjTqqVlnn8tf0qd9OCunKT/j8UZv4oosMmaWxfea/6Yd9hFu/+quvQfWwgKbz3 OhbHwASkxMPZsJKafsEiS2GnDk5d9rdz27toIDzTORlEGbggyyyoQzo+aZjQAhS2n8 JY3dovZtyXxkLVsKdJraJFVrz0ma4djpMBaH2teKOwj7qEQuNGWx7mjihkxDgBiQDN gmLdCMfAbsrGg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH] usb: typec: fusb302: Send PD messages longer than one SMBus block Reply-To: sashiko-reviews@lists.linux.dev To: "Alexey Charkov" Cc: linux-usb@vger.kernel.org In-Reply-To: <20261102-fusb302-long-tx-v1-1-0d2719488c3b@flipper.net> References: <20261102-fusb302-long-tx-v1-1-0d2719488c3b@flipper.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 02 Nov 2026 13:47:40 +0000 X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > The whole message, tokens included, goes to the FIFO in a single SMBus > block write, which carries at most 32 bytes and silently drops the rest. > A message with six or seven data objects needs up to 39, so it loses its > closing tokens including TXON: the chip never sends it, the transmission > times out, and the truncated bytes stay in the TX FIFO ahead of the next > message. A Discover Identity ACK carrying a full set of sink-vdos is one > such message, as is a Source_Capabilities with six or seven PDOs. >=20 > Write the message in chunks of at most one SMBus block. The FIFOS > register has no address auto-increment and queues every byte written to > it, so consecutive writes append to the 48-byte TX FIFO. TXON is the > one token that is not queued but starts the transmitter as soon as it is > written. It still comes last, so transmission begins only once the whole > message is in the FIFO, as the datasheet recommends. >=20 > Flush the TX FIFO if a write fails, so that a partial message cannot > stay queued and go out together with the next one as a garbled frame. >=20 > Signed-off-by: Alexey Charkov Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261102-fusb302-lo= ng-tx-v1-1-0d2719488c3b@flipper.net?part=3D1