From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756561AbcAZB6L (ORCPT ); Mon, 25 Jan 2016 20:58:11 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:42388 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750997AbcAZB6J (ORCPT ); Mon, 25 Jan 2016 20:58:09 -0500 Subject: Re: [PATCH v3] watchdog: Add watchdog timer support for the WinSystems EBC-C384 To: William Breathitt Gray , One Thousand Gnomes References: <20160125190942.GA6824@sophia> <20160125192810.2487661b@lxorguk.ukuu.org.uk> <56A6889E.60208@roeck-us.net> <56A6B198.2080205@gmail.com> Cc: wim@iguana.be, linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org From: Guenter Roeck Message-ID: <56A6D2AE.6010703@roeck-us.net> Date: Mon, 25 Jan 2016 17:58:06 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <56A6B198.2080205@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/25/2016 03:36 PM, William Breathitt Gray wrote: > On 01/25/2016 03:42 PM, Guenter Roeck wrote: >> On 01/25/2016 11:28 AM, One Thousand Gnomes wrote: >>> If ask for 299 seconds surely I should get 300 not 240 ? >>> (Whether to round off or round up is an interesting question for the >>> middle range - does it go off early or late - I'd have said late but...) >>> >> >> Matter of endless discussion. Some argue that the value should be rounded >> up, some argue that it should be rounded down, some argue that it should >> be rounded to the closest match. Each camp has its own valid arguments. >> I usually leave it up to the driver's author to decide, with a slight >> preference to never select a value larger than requested. > > I implemented it to round down simply because it was the simplest > solution (i.e. integer truncation). Although I see merit in an > implementation that rounds to the closest valid value, I'll keep the > current implementation for now due to its simplicity; if enough users of > the driver prefer a different implementation, then I'll add it in a > later patch. > >>> Is there no ACPI entry for it ? >>> >> Same here. As long as the board is identified, I tend to leave it up >> to the driver author to decide _how_ to identify it. >> >> Only question for me would be if the watchdog timer is implemented >> in a Super-IO chip, and if so, if it would be possible to use the chip >> identification instead of a DMI (or ACPI) entry to instantiate the driver. > > I do not believe there is an ACPI entry for it. Interestingly, the > watchdog timer BIOS configuration option for this motherboard is listed > under the Super I/O menu; perhaps this watchdog timer is implemented in > the Super I/O chip. > > The manual for this motherboard does not provide much information about > the Super I/O chip (no model number, etc.), and neither sensors-detect > nor superiotool was able to detect it. I've sent an email to the > motherboard company (WinSystems) requesting further information about > the Super I/O chip and whether the watchdog timer is built-in to the > Super I/O chip. > I had a close look at the board pictures in the manual. Looks like there is a NCT7802Y hardware monitoring chip on the board. This suggests that the Super-IO chip does probably not implement hardware monitoring. Not that it helps much to know that, but it reduces the possibilities. There is also a pretty large Lattice FPGA on the board, which makes it at least somewhat likely that the functionality is implemented in that FPGA. Guenter