From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52503) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKOn0-0000qF-Sw for qemu-devel@nongnu.org; Tue, 05 Jul 2016 07:45:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bKOmw-0005FE-Jr for qemu-devel@nongnu.org; Tue, 05 Jul 2016 07:45:17 -0400 Received: from mail-wm0-x243.google.com ([2a00:1450:400c:c09::243]:34179) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKOmw-0005FA-Ck for qemu-devel@nongnu.org; Tue, 05 Jul 2016 07:45:14 -0400 Received: by mail-wm0-x243.google.com with SMTP id 187so28133510wmz.1 for ; Tue, 05 Jul 2016 04:45:14 -0700 (PDT) Sender: Paolo Bonzini References: <1467664794-31002-1-git-send-email-kraxel@redhat.com> <20160705080605.GA6553@redhat.com> <1467712848.12358.21.camel@redhat.com> <20160705100711.GJ6553@redhat.com> From: Paolo Bonzini Message-ID: <06b3f67a-a3e8-021b-6b13-33062bd2d259@redhat.com> Date: Tue, 5 Jul 2016 13:45:10 +0200 MIME-Version: 1.0 In-Reply-To: <20160705100711.GJ6553@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v2 0/3] seabios: add serial console support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" , Gerd Hoffmann Cc: seabios@seabios.org, qemu-devel@nongnu.org On 05/07/2016 12:07, Daniel P. Berrange wrote: >> > What the final default behavior will be is not clear yet. Not enabled? >> > Enabled in case no VGA is present? Enabled unconditionally (simliar to >> > ovmf)? > (Bitter) experiance in libvirt has shown us that magically enabling > things based on whether or not some other feature is enabled leads > to pain and suffering in the long term. > > So from libvirt's POV, we would like an explicit command line flag > to turn on/off seabios serial console support, with no dependancy > on whether VGA is present or not. With my other proposal, "-machine graphics=no -device sga" should do it. However, for libvirt to do this, it should stop using "-nographic" to disable all display backends, and instead use "-display none". The advantage is that neither "-display none" nor "-machine graphics=no" do any magic redirection of the monitor and the serial ports to stdio. "-display none" is supported since QEMU 1.0. For old QEMU without query-command-line-options it can be scraped from help text; for new QEMU with query-command-line-options it can be treated as always there. Paolo