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([2400:4050:c360:8200:8ae8:3c4:c0da:7419]) by smtp.gmail.com with ESMTPSA id b1-20020a63d801000000b0046ff7db0984sm2842628pgh.72.2022.12.01.10.14.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 01 Dec 2022 10:14:45 -0800 (PST) Message-ID: <18c884cb-dd73-09eb-65da-604cf45cb1b4@daynix.com> Date: Fri, 2 Dec 2022 03:14:41 +0900 Precedence: bulk X-Mailing-List: asahi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH] arch: arm64: dts: apple: Remove stdout-path Content-Language: en-US To: Hector Martin , Mark Kettenis Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, asahi@lists.linux.dev, krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org, alyssa@rosenzweig.io, sven@svenpeter.dev References: <20221201103651.27807-1-akihiko.odaki@daynix.com> <877czb42wk.fsf@bloch.sibelius.xs4all.nl> <8b3c4fe0-4a81-ba47-2f01-3686cfdbd519@daynix.com> <647b6572-e5d1-d243-283e-616cef15a1f5@marcan.st> From: Akihiko Odaki In-Reply-To: <647b6572-e5d1-d243-283e-616cef15a1f5@marcan.st> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2022/12/02 2:46, Hector Martin wrote: > On 02/12/2022 01.38, Akihiko Odaki wrote: >> >> In contrary, if you boot the kernel without the hypervisor >> >> feature and this change, you will completely lose the console. >> > >> > How so? The console goes to both places with stdout-path set to serial0. >> > What it *does* change is where input is accepted prior to getty startup >> > (which is why u-boot specifically conditions this on keyboard presence, >> > modulo the USB issue - because if you *don't* have a keyboard then tty >> > keyboard input is useless). But if you're booting kernels without u-boot >> > along the way, you're probably doing it from the hypervisor or linux.py >> > anyway, especially if you plan to do something like "init=/bin/sh", >> > because without u-boot (+ optionally some EFI loader) there is no way of >> > editing command line arguments at boot time stand-alone. >> >> Well, that is not exactly the behavior I saw. In my case, if stdout-path >> is pointed to serial, there is no output on the framebuffer, and it just >> printed "_". >> >> It looks like the kernel only outputs to either of serial and >> framebuffer, not both. > > That is not what I've seen in all of my hypervisor runs since the dawn > of time. You get log output on both. > >> What I experienced is that when I directly booted the kernel from m1n1 >> without hypervisor, it showed no output to the display even though the >> same kernel worked with U-Boot. While I could tell it used wrong console >> by running the hypervisor, I wondered why it behaves differently without >> U-Boot, and found the aforementioned U-Boot change, coming up with this >> patch. > > Then it sounds like something else is different about our setups, > because I've booted the kernel from linux.py hundreds of times and I get > output on both. Looking through the console code, the VT console gets > added and enabled really early, and the subsequent serial console > registration later does not disable it. > > Look for "console: colour dummy device 80x25". It should be immediately > followed by "printk: console [tty0] enabled", and this should all come > well before the ttySAC0 serial stuff shows up. > > - Hector I think I understand the situation now. By "console", I was meaning the input and output of init, but I failed to clarify that and you thought it referring to kernel message output. I saw no messages earlier than init because my kernel command line has loglevel=3. Regards, Akihiko Odaki 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3C1D4C4332F for ; Thu, 1 Dec 2022 23:06:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=cPwI7FeT/KkDPJw1LZu6luuHy9P2rqNuWeFfU1Djm7Y=; b=2KJycgLZj3Q5a1 0lctJ8izHzsiVTomoVZs0yRlPKEb728vMg9ArUtcW4lBHTqJS2y4Xjkv796SPG88hrhI0BY7sB80u F9KxMMOglHQ0KZuMHJuYxBY1CqAEP8FlBJVD5Q2FZHgEmB/0p4UaAtvJCA9n1D5S9imXJ7uUkS8fc qOvXlcj4F29tQq7GGAbXCZku6NFi1FDG34HATp9nMESYzbPMcMxNk/G/Z0IB69uPl8O1MUYJ6TxFG gd5WUGHohgz/2srlcCtTZUex3OwdYfSrGDeuYHI+9bC9eGpn4oK3Vws0xmjaTk1i/aLnfhaDn9ZCU iO/W9VviqaDV7ksSYfrg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p0scH-00BWgU-Sa; Thu, 01 Dec 2022 23:05:18 +0000 Received: from mail-pg1-x536.google.com ([2607:f8b0:4864:20::536]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p0o5A-009X1n-7w for linux-arm-kernel@lists.infradead.org; Thu, 01 Dec 2022 18:14:50 +0000 Received: by mail-pg1-x536.google.com with SMTP id 6so2342684pgm.6 for ; Thu, 01 Dec 2022 10:14:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=daynix-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=+qiP+aVyEbFOin+Fo/Yz6dh5ehlyeto99kkZi+uNlNg=; b=bLwHx176LOszJh7EjFmxlHoRSrusawe1m/8ONFIvi20Ao1VaNovHngA/dkeAr9PdM6 HXyqLmIOclACQAJz9XvahXKcNR64jiGkSV2gp2VVafJ/t/8EGFbJrIYhGEV1aMX5xqTt j1+/A/Mk4bf9xbt+jBLBQywuGUSoPYAuKjqywUfWHdD/IzmCctJIGHC8g8PIOO8gna0z LZ1558q3nJqSv++SBilMpXNgyiGoLv103hh+ZzCzwnxRfKvhjbtqZtXqMpc2D5h9/eVt MSjyIjF5HqSDRPNLRETVpOLf/BOuCy2GfaRce6VtPi400GwVMFdkBA1JjPHuntxdehAV hrPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+qiP+aVyEbFOin+Fo/Yz6dh5ehlyeto99kkZi+uNlNg=; b=GLGvL84F84MAjaFW/8QDZ2VCVTpdEZw0Uoi7xpB1x5CAKiZZSPac0KDjFiDFRPZwx5 ja748bZ+VaXQ9+s3KumCWJWGaj4oAGNGjX2kqQddv7Vc7IuqSuLQEsT+jnWu2VJApzHk WqnzFEreJgQcvt4BS4p7ptRI0PwNOw1NYr1IeJJEn4rMzknkOO6tI4Ryn5RLgywwzRbz /0jIMW5CUzo0/IeiX+T9kO4L8EPHE2on5sJ9OO1kJYE+mtwMq3a7ok9zFfXL3n2Dg51v 4glC9dk9n4UMP6V3Fyb9OpUW6BuMylHZlhzgIIo94GuR5czNBU3xVeD386h8tBErf+jh h6FQ== X-Gm-Message-State: ANoB5pnKZwXGNO9r7rfBRRYo1LyR89kJIdzJoO6DZ8GGTRChIswo6i3J qPCOHxn1XEviHRNlt6+eYyNmEg== X-Google-Smtp-Source: AA0mqf4B6/UAlIPQX5wvlJ3k48CdDnGeviR46Lrs1HEVHn73FAxfx55icdrfZVrW9OOfLpFuIcVuaw== X-Received: by 2002:a62:1417:0:b0:575:c993:acbe with SMTP id 23-20020a621417000000b00575c993acbemr11000843pfu.2.1669918485410; Thu, 01 Dec 2022 10:14:45 -0800 (PST) Received: from ?IPV6:2400:4050:c360:8200:8ae8:3c4:c0da:7419? ([2400:4050:c360:8200:8ae8:3c4:c0da:7419]) by smtp.gmail.com with ESMTPSA id b1-20020a63d801000000b0046ff7db0984sm2842628pgh.72.2022.12.01.10.14.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 01 Dec 2022 10:14:45 -0800 (PST) Message-ID: <18c884cb-dd73-09eb-65da-604cf45cb1b4@daynix.com> Date: Fri, 2 Dec 2022 03:14:41 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH] arch: arm64: dts: apple: Remove stdout-path Content-Language: en-US To: Hector Martin , Mark Kettenis Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, asahi@lists.linux.dev, krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org, alyssa@rosenzweig.io, sven@svenpeter.dev References: <20221201103651.27807-1-akihiko.odaki@daynix.com> <877czb42wk.fsf@bloch.sibelius.xs4all.nl> <8b3c4fe0-4a81-ba47-2f01-3686cfdbd519@daynix.com> <647b6572-e5d1-d243-283e-616cef15a1f5@marcan.st> From: Akihiko Odaki In-Reply-To: <647b6572-e5d1-d243-283e-616cef15a1f5@marcan.st> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221201_101448_549001_11387076 X-CRM114-Status: GOOD ( 27.64 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2022/12/02 2:46, Hector Martin wrote: > On 02/12/2022 01.38, Akihiko Odaki wrote: >> >> In contrary, if you boot the kernel without the hypervisor >> >> feature and this change, you will completely lose the console. >> > >> > How so? The console goes to both places with stdout-path set to serial0. >> > What it *does* change is where input is accepted prior to getty startup >> > (which is why u-boot specifically conditions this on keyboard presence, >> > modulo the USB issue - because if you *don't* have a keyboard then tty >> > keyboard input is useless). But if you're booting kernels without u-boot >> > along the way, you're probably doing it from the hypervisor or linux.py >> > anyway, especially if you plan to do something like "init=/bin/sh", >> > because without u-boot (+ optionally some EFI loader) there is no way of >> > editing command line arguments at boot time stand-alone. >> >> Well, that is not exactly the behavior I saw. In my case, if stdout-path >> is pointed to serial, there is no output on the framebuffer, and it just >> printed "_". >> >> It looks like the kernel only outputs to either of serial and >> framebuffer, not both. > > That is not what I've seen in all of my hypervisor runs since the dawn > of time. You get log output on both. > >> What I experienced is that when I directly booted the kernel from m1n1 >> without hypervisor, it showed no output to the display even though the >> same kernel worked with U-Boot. While I could tell it used wrong console >> by running the hypervisor, I wondered why it behaves differently without >> U-Boot, and found the aforementioned U-Boot change, coming up with this >> patch. > > Then it sounds like something else is different about our setups, > because I've booted the kernel from linux.py hundreds of times and I get > output on both. Looking through the console code, the VT console gets > added and enabled really early, and the subsequent serial console > registration later does not disable it. > > Look for "console: colour dummy device 80x25". It should be immediately > followed by "printk: console [tty0] enabled", and this should all come > well before the ttySAC0 serial stuff shows up. > > - Hector I think I understand the situation now. By "console", I was meaning the input and output of init, but I failed to clarify that and you thought it referring to kernel message output. I saw no messages earlier than init because my kernel command line has loglevel=3. Regards, Akihiko Odaki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel