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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 79111C3A5A1 for ; Wed, 28 Aug 2019 16:27:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 231C222CED for ; Wed, 28 Aug 2019 16:27:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fnarfbargle.com header.i=@fnarfbargle.com header.b="kB3cMATD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726917AbfH1Q1k (ORCPT ); Wed, 28 Aug 2019 12:27:40 -0400 Received: from ns3.fnarfbargle.com ([103.4.19.87]:42556 "EHLO ns3.fnarfbargle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726881AbfH1Q1h (ORCPT ); Wed, 28 Aug 2019 12:27:37 -0400 Received: from [10.8.0.1] (helo=srv.home ident=heh12100) by ns3.fnarfbargle.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1i30mc-000414-Eo; Thu, 29 Aug 2019 00:26:54 +0800 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fnarfbargle.com; s=mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=Q6pQA2hBI5LX+VRBBaU8DvqsCNBqlofTcGdZN0ScIEs=; b=kB3cMATDwH03UOlLtYDNWrVGmDabraS9P1sO7EIjlbdPIxkfOR4Lgsn2/GBI/z80XNLjM+xwiZNIxz6S+9zd8bxQ4cp7goYvOMjZHPrQ411tcJYn6pG770qyAuyhVHdAgpw8kHjk6MF73UOhFTU9cpFdbNZ9+I4CT76ItngB7sg=; Subject: Re: Thunderbolt DP oddity on v5.2.9 on iMac 12,2 To: Mika Westerberg Cc: linux-kernel@vger.kernel.org, michael.jamet@intel.com, YehezkelShB@gmail.com References: <472bee84-d62b-bfcb-eb83-db881165756b@fnarfbargle.com> <20190828073302.GO3177@lahna.fi.intel.com> <7c9474d2-d948-4d1d-6f7b-94335b8b1f15@fnarfbargle.com> <20190828102342.GT3177@lahna.fi.intel.com> <20190828131943.GZ3177@lahna.fi.intel.com> From: Brad Campbell Message-ID: Date: Thu, 29 Aug 2019 00:27:08 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190828131943.GZ3177@lahna.fi.intel.com> 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 28/8/19 21:19, Mika Westerberg wrote: > On Wed, Aug 28, 2019 at 06:43:35PM +0800, Brad Campbell wrote: >> On 28/8/19 6:23 pm, Mika Westerberg wrote: >> >>> On Wed, Aug 28, 2019 at 05:12:00PM +0800, Brad Campbell wrote: >>> >>> Apart from the warning in the log (which is not fatal, I'll look into >>> it) to me the second path setup looks fine. >>> >>> Can you do one more experiment? Boot the system up without anything >>> connected and then plug both monitors. Does it work? >>> >> Aside from head ordering issues in X it works just fine. >> I've attached the dmesg. Boot with nothing plugged in, then plug in 0-1 and >> 0-3 in that order. > OK, thanks for checking. So when Linux is in complete control both DP > tunnels get created properly. I suspect there is something different > what the firmware does compared to other Macs I've been using and that > causes the driver to fail to discover all the paths. I will take a look > at this but I'm away tomorrow and friday so it goes to next week. It wouldn't surprise me if the firmware was doing something funky. It was one of the first Thunderbolt equipped models and the support docs explicitly say only one Thunderbolt display in Windows and two in later versions of OSX. It almost needs a quirk to say "firmware does something we don't like, reset the controller and re-discover from scratch". Anyway, I'm not in any hurry. It doesn't get rebooted often and it's not in any way preventing me using the machine. In fact, upgrading the third head from an old 24" 1920x1200 to the second Thunderbolt display has been invaluable. > BTW, have you tried to chain the two monitors? Not yet, but it was something I've been considering. I'll give it a go tomorrow. Due to cable length vs display dimensions it'll require me cleaning my desk, and that takes some forward planning. -- An expert is a person who has found out by his own painful experience all the mistakes that one can make in a very narrow field. - Niels Bohr