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=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 A1F28C4321A for ; Fri, 26 Apr 2019 08:42:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7473C20652 for ; Fri, 26 Apr 2019 08:42:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=brainfault-org.20150623.gappssmtp.com header.i=@brainfault-org.20150623.gappssmtp.com header.b="n/+hgzau" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726366AbfDZIms (ORCPT ); Fri, 26 Apr 2019 04:42:48 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:35612 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725935AbfDZImr (ORCPT ); Fri, 26 Apr 2019 04:42:47 -0400 Received: by mail-wr1-f67.google.com with SMTP id f7so3309303wrs.2 for ; Fri, 26 Apr 2019 01:42:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=brainfault-org.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=y9MU1IdAQeQ47a3CDcXM8eoZTJOFdkZQ9xHCLPVf5Nw=; b=n/+hgzauxCACf37JbCqubpc6ejARtZebct9i9I1Mt2FY8Saok6AmUEEwzfMAD3wVjP m7OYKBxTAi7BbqonQnJVQrQ8jQRNo8PaELaUVe6FizWzGp61N9dyHyo9MzkBuiBFs16+ sAW0KmcYlDBDIjsQv8CagduWQIbY13uFNSRDj6uYuvaj7XLhxWRfN8qcllhxYX1RwyVT 3Vtp3r0DX2yg8jjI7sFAVVTM6i/elxwtZTWpTdpTZLE7FtwGqVKngGxX+gH17w0q+yWg znrOLU0IGOQtXxMh5caRX3xzPyQCUNX7I4EcybbV6csSurhkOkROPjcLE2ccGf4FlQqk 71Rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=y9MU1IdAQeQ47a3CDcXM8eoZTJOFdkZQ9xHCLPVf5Nw=; b=Y4BjDFpkSrOGa/x2tjlXtBDQt/n1qsSF8BISfMVhCkjPpZePvRRqhnjfh9yCQvFb/+ Ltjc2fXryF9GYkkKohffjVMHNon9Tt0zNMmdKnCTSDg6aNa9aXIhte+Lwg0lFKt+EjCf 8iKjy28wxUCcjHEn8/dlzv/csFqESNruYYT0jrblktWTmy4TdJZwGDYFD1bGVf3HXf+Y 1chGfamsR9GpgJ/CuH+ZmR7A41jX03gZpiubpVHvNV3uOG9sK9wTBYAVV6sp8/A5nU10 z8kjTt5iYlViZMTK8n7aL3skdXIgVUPLg1UQ3c0FG8iZxPMOeViRlNRvalwI5e0PuWMW 4ktw== X-Gm-Message-State: APjAAAUCrDkHXkdkKe9cFzjQlfwEJsXJUBy//Yj9eXTvI+ThixNnWk5v scLrlHVAtU9X/HRJ2tq3OJnU39HLQhkUMrJax/X61ete X-Google-Smtp-Source: APXvYqzMNhhXRFesWECwTBM7WFb1r0WtOR9RtHwmmhiGhakLC1n7xqdll33oaj9riCM93DkXikdAgfKkPd8Gme9hb1w= X-Received: by 2002:a5d:5346:: with SMTP id t6mr9152799wrv.59.1556268165924; Fri, 26 Apr 2019 01:42:45 -0700 (PDT) MIME-Version: 1.0 References: <20190425133435.56065-1-anup.patel@wdc.com> <9a8be7ef-e62e-2a93-9170-e3dc70dfb25f@wdc.com> <20190426062133.GA28529@infradead.org> In-Reply-To: <20190426062133.GA28529@infradead.org> From: Anup Patel Date: Fri, 26 Apr 2019 14:12:34 +0530 Message-ID: Subject: Re: [PATCH] tty: Don't force RISCV SBI console as preferred console To: Christoph Hellwig Cc: Atish Patra , Palmer Dabbelt , Greg Kroah-Hartman , Anup Patel , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Albert Ou , Jiri Slaby , "linux-riscv@lists.infradead.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 26, 2019 at 11:51 AM Christoph Hellwig wrote: > > On Thu, Apr 25, 2019 at 09:41:21PM -0700, Atish Patra wrote: > > Do we even need HVC_SBI console to be enabled by default? Disabling > > CONFIG_HVC_RISCV_SBI seems to be fine while running in QEMU. > > > > If we don't need it, I suggest we should remove the config option from > > defconfig in addition to this patch. > > I think the whole concept of the SBI console is a little dangerous. > It means that for one piece of physical hardware (usually the uart) > we have two entiries (the M-mode firmware and the OS) in control, > which tends to rarely end well. I think the SBI console is only useful for early SOC bringup and early SOC debugging when most drivers are not available in upstream kernel. It cannot (and should not) be used in production deployments. Regards, Anup 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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 11BADC4321A for ; Fri, 26 Apr 2019 08:42:58 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D99ED20652 for ; Fri, 26 Apr 2019 08:42:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="SinW6tWZ"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=brainfault-org.20150623.gappssmtp.com header.i=@brainfault-org.20150623.gappssmtp.com header.b="n/+hgzau" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D99ED20652 Authentication-Results: mail.kernel.org; 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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=y9MU1IdAQeQ47a3CDcXM8eoZTJOFdkZQ9xHCLPVf5Nw=; b=F5F7V50MTKoZ5A60JNJzI9dBIqs2oTezeDpU7V3DQ58ZAjOaEFdTqLZqVSAweFhp3c upeG/2gVR4dxLgFqNiJR43/dwEPceA9/laehWVPLVtl6dU/aXB4O0Kx33tGxMVywlelR tzjXx9siqxei/SQFFg/VPIxi2k4NoZ6Wc6eNdbfXXZGnrZEDvIxN2E2Q6vOimghTFOdO CR+DAZcF5oW3/7ZXyL/90MbcitfEXhW2BcJ5akjX0ydIUIBqOLJTC6U54CJp+7EDRMW8 DXo+P7w7BlOttlpgIoSOFAaQEQXjO3quPgR/Ced696y1wU1Mlk7c5QHZXu9xxJGTlPhY RoGg== X-Gm-Message-State: APjAAAWH/8B0IAYY3E0yFBD9m+nhWS5W88tyindHeS/eaysiVUVQk82d 2CqVkNumz+KKNnclLAn24zQWUp/kNkAgw1hLpaISlA== X-Google-Smtp-Source: APXvYqzMNhhXRFesWECwTBM7WFb1r0WtOR9RtHwmmhiGhakLC1n7xqdll33oaj9riCM93DkXikdAgfKkPd8Gme9hb1w= X-Received: by 2002:a5d:5346:: with SMTP id t6mr9152799wrv.59.1556268165924; Fri, 26 Apr 2019 01:42:45 -0700 (PDT) MIME-Version: 1.0 References: <20190425133435.56065-1-anup.patel@wdc.com> <9a8be7ef-e62e-2a93-9170-e3dc70dfb25f@wdc.com> <20190426062133.GA28529@infradead.org> In-Reply-To: <20190426062133.GA28529@infradead.org> From: Anup Patel Date: Fri, 26 Apr 2019 14:12:34 +0530 Message-ID: Subject: Re: [PATCH] tty: Don't force RISCV SBI console as preferred console To: Christoph Hellwig X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190426_014249_840337_6116E6AE X-CRM114-Status: GOOD ( 12.23 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Palmer Dabbelt , Greg Kroah-Hartman , Anup Patel , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Atish Patra , Albert Ou , Jiri Slaby , "linux-riscv@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org On Fri, Apr 26, 2019 at 11:51 AM Christoph Hellwig wrote: > > On Thu, Apr 25, 2019 at 09:41:21PM -0700, Atish Patra wrote: > > Do we even need HVC_SBI console to be enabled by default? Disabling > > CONFIG_HVC_RISCV_SBI seems to be fine while running in QEMU. > > > > If we don't need it, I suggest we should remove the config option from > > defconfig in addition to this patch. > > I think the whole concept of the SBI console is a little dangerous. > It means that for one piece of physical hardware (usually the uart) > we have two entiries (the M-mode firmware and the OS) in control, > which tends to rarely end well. I think the SBI console is only useful for early SOC bringup and early SOC debugging when most drivers are not available in upstream kernel. It cannot (and should not) be used in production deployments. Regards, Anup _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv