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=1794698704; b=pRkaiF3SxsAPrYzQjhYuQAaEEyCwuBpjnW67tNu8mWKD43tYPQHahxLLjFw1XJ0r7JBC 0HebOizFmaeQJanqj6vDOM3rd6xUeFL1tnGAgTiZ0paQgFwzC3B499TTE+nOJg5oxEZ5k TE5k3F3E//3xO8NasdHw1iWDBz6CnjVtqVfj6UtD4qHvtub/gItmB/9l50umYYeiYLYrM X338eDFnt31fIFvrcaU5XYjkQ1D0z4JvwBI5BvGiPH+873ek/xQ63pkTHtxlNeO6g8QJO T17jZyEQgCCKJXZ+r4/w8Dk6A/tPGWL9XxgW+5PSdk6ols9GOHsAQLI9Yx37j8K9euQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794698704; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=us3d6XmMzpC3a5DSZd6uicMhySCgUh1JFzIyzKD3OcI=; b=XoBvj5NP3qccjr5SYjTkgbxDGMdrFbWSKJYPvL/jwy3k5NnEWZdowl9k7+MSYBPGayeK Vs2MJd/tehCZdLeAABsxOaHP+je788Z0bdMxlmp7jWyaphk+fBYC9vEhxGTcRqJtXb7Po h3eUth/m1bR4Vkucha2vsPsFBmCFs2d1TONDDRUttsHbLfP3gqI5DSK8t1tv27WbBZKRC e64DBY9DLOQ962IuPmUeE94wsds3m50YHN6/wdW0gC/ObDRb4/5TX9j3CpPpQcopZKZsB XPdU0XuBubHgdfCBIAQGi1Lqn7p5tg/rLGnmwH4N3cHIjSYGx0JuCnvdKACm7KWtI1A== 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=C4GGgvai; 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 B6A35606A323 for ; Sat, 14 Nov 2026 23:25:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=C4GGgvai Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E1091F000C4; Sat, 14 Nov 2026 23:25:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794698704; bh=us3d6XmMzpC3a5DSZd6uicMhySCgUh1JFzIyzKD3OcI=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=C4GGgvaihqcygHwmudNtjgrtBTcAwM+U4ABaCIOL/ZGXCmzYpTeqswSsYHp0IzjX3 ZcSvD218u8gprwPXCM+GKuuGOhJKCjA/NJeeepNEMMSoiuVnkRCdLITrsEz+EmQw8T KYrRADODnM+8QbqlxUBj26sBPTQVNT7S+YavmflUDilotY+3tjDHf/HiIVh9RITEcH m4E9LjsMmQEjPfB4X1mVJW0IjlS5CfBGLXONxFBRCFbFX5uK1vGyMCL6CNHQ4Lms66 LW1h04khd2YmEdnMCAcOpzFLmtcnmZGUR5zJKTZxV1+yaXflDQe1ttfx4UVSqV7pLx UQbnUGQlLHTcA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 15/16] HID: ft260: i2c: recover a bus held by a slave Reply-To: sashiko-reviews@lists.linux.dev To: "Michael Zaidman" Cc: linux-serial@vger.kernel.org In-Reply-To: <20261114230800.1344401-16-michael.zaidman@gmail.com> References: <20261114230800.1344401-1-michael.zaidman@gmail.com> <20261114230800.1344401-16-michael.zaidman@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 14 Nov 2026 23:25:03 +0000 X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > An SMBus block read takes the first byte the slave sends as the block > length. An EEPROM has no length byte, it answers with stored data, and > ft260_smbus_xfer() rejects a value above I2C_SMBUS_BLOCK_MAX. That > count phase carries no STOP, so the slave keeps SDA low while it waits > for the next clock. FT260_SET_I2C_RESET restarts the controller but > does not clock the bus, the chip cannot put a STOP on the line, and > every later START ends in arbitration lost. >=20 > A 24c02 holds 0x68 at offset 0x80, so on that bus >=20 > i2cget -y 0 0x50 0x80 s > ft260 0003:0403:6030.0011: smbus block read: invalid count 104 from sla= ve 0x50 >=20 > killed the bus: every transfer after it failed with bus_status 0x72 > (bus busy, controller idle, arbitration lost, error). The sysfs > [ ... ] > recovery: a full i2cdetect scan of 112 addresses logs no "recovering" > line. >=20 > Fixes: 2d68d67151eb ("HID: ft260: fix SMBus block read protocol handling") > Signed-off-by: Michael Zaidman Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261114230800.1344= 401-1-michael.zaidman@gmail.com?part=3D15