From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53431) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dSjJn-0007bN-4G for qemu-devel@nongnu.org; Wed, 05 Jul 2017 08:22:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dSjJk-0007Ff-0F for qemu-devel@nongnu.org; Wed, 05 Jul 2017 08:22:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34908) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dSjJj-0007FR-Pr for qemu-devel@nongnu.org; Wed, 05 Jul 2017 08:22:03 -0400 Date: Wed, 5 Jul 2017 20:22:00 +0800 From: Fam Zheng Message-ID: <20170705122200.GH29382@lemon.lan> References: <1499237876.3041.4.camel@linux.intel.com> <20170705110431.GE22008@redhat.com> <20170705114411.GE29382@lemon.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] change x86 default machine type to Q35? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: "Daniel P. Berrange" , Chao Peng , "Tian, Kevin" , qemu-devel@nongnu.org On Wed, 07/05 13:58, Thomas Huth wrote: > On 05.07.2017 13:44, Fam Zheng wrote: > > On Wed, 07/05 12:04, Daniel P. Berrange wrote: > >> While you can say people should just add '-M pc' that isn't a nice > >> user experiance, because it makes the assumption that people actually > >> understand what caused their breakage. When the incompatibilities > >> arise the error messages are unlikely to give any hint to users that > >> the problems are caused by the machine type change. So unless someone > >> is very familiar with debugging QEMU, they're not going to realize > >> that '-M pc' will fix their problem. > > > > While we change the default, can we start to print a message like 'machine type > > ("-M" option) not specified, default to Q35. If you find compatibility issues, > > try "-M pc"'? > > Or we could simply remove the default machine type completely for a > couple of releases? That would force people to update their script with > "-M pc" ... and once this has been established, we can finally make q35 > the default? I wouldn't do that.. Defaults are for those who don't care about setting it, or want something that just works, by default. It's fine not to provide a default machine type if we decide there isn't a clear win, just like arm, but IMHO removing it just to restore it later in order to educate people makes a very poor experience. Fam