From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6511AC4CED1 for ; Fri, 4 Oct 2019 11:50:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 46C1720862 for ; Fri, 4 Oct 2019 11:50:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730769AbfJDLup (ORCPT ); Fri, 4 Oct 2019 07:50:45 -0400 Received: from jpvw.nl ([80.127.100.2]:49920 "EHLO jpvw.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728357AbfJDLup (ORCPT ); Fri, 4 Oct 2019 07:50:45 -0400 Received: from localhost ([127.0.0.1] helo=jpvw.nl) by jpvw.nl with esmtp (Exim 4.92) (envelope-from ) id 1iGM6d-0005JL-F7; Fri, 04 Oct 2019 13:50:43 +0200 Subject: Re: [PATCH] si2157: Add support for Logilink VG0022A. To: Mauro Carvalho Chehab , Gonsolo Cc: crope@iki.fi, Sean Young , linux-media@vger.kernel.org, Linux Kernel References: <29ab2e43-4374-a3ea-6ae1-a4267867eaa4@jpvw.nl> <20191002154922.7f1cfc76@coco.lan> <20191003080539.2b13c03b@coco.lan> <20191003120238.75811da6@coco.lan> <20191003160336.GA5125@Limone> <20191003130909.01d29b77@coco.lan> <20191003162326.GA2727@Limone> <20191003144225.0137bf6c@coco.lan> <20191003183200.GA2631@Limone> <20191003163914.7c384d36@coco.lan> <20191003164426.6da8538f@coco.lan> <20191003170329.3624f7f2@coco.lan> From: JP Message-ID: <23d9856c-cc12-7212-9126-90d80f67abfb@jpvw.nl> Date: Fri, 4 Oct 2019 13:50:43 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191003170329.3624f7f2@coco.lan> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/3/19 10:03 PM, Mauro Carvalho Chehab wrote: > Em Thu, 3 Oct 2019 21:51:35 +0200 > Gonsolo escreveu: > >>> 1) The firmware file is likely at the Windows driver for this device >>> (probably using a different format). It should be possible to get >>> it from there. >> If you tell me how I'm willing to do this. :) > I don't know. I was not the one that extracted the firmware. I guess > Antti did it. > > I suspect that there are some comments about that in the past at the > ML. seek at lore.kernel.org. > >>> 2) Another possibility would be to add a way to tell the si2168 driver >>> to not try to load a firmware, using the original one. That would >>> require adding a field at si2168_config to allow signalizing to it >>> that it should not try to load a firmware file, and add a quirk at >>> the af9035 that would set such flag for Logilink VG0022A. >> I don't get this. Which firmware, si2168 or si2157? > The one that it is causing the problem. If I understood well, the > culprit was the si2168 firmware. > >> I'm still for option 3: If there is a bogus chip revision number it's >> likely the VG0022A and we can safely set fw to NULL, in which case >> everything works. >> All already working devices will continue to work as before. >> With a low probability there are other devices that will return 0xffff >> but a) they didn't work until now and b) they receive a clear message >> that they return bogus numbers and this works just for the VG0022A, in >> which case this hardware can be tested. >> At last, *my* VG0022A will work without a custom kernel which I'm a >> big fan of. :)) >> >> Are there any counterarguments except that it is not the cleanest >> solution in the universe? ;) > That's a really bad solution. Returning 0xff is what happens when > things go wrong during I2C transfers. Several problems can cause it, > including device misfunction. Every time someone comes with a patch > trying to ignore it, things go sideways for other devices (existing > or future ones). > > Ignoring errors is always a bad idea. add module param say 'gonso_hack_vg0022a' if true, act on error by setting a flag if this flag is set don't load firmware Jan Pieter.