From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42965) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VEeIY-0002Ja-Um for qemu-devel@nongnu.org; Wed, 28 Aug 2013 07:52:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VEeIQ-0003ak-82 for qemu-devel@nongnu.org; Wed, 28 Aug 2013 07:52:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40450) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VEeIQ-0003aX-0o for qemu-devel@nongnu.org; Wed, 28 Aug 2013 07:52:22 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r7SBqLA3029739 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 28 Aug 2013 07:52:21 -0400 Message-ID: <1377690738.20403.70.camel@nilsson.home.kraxel.org> From: Gerd Hoffmann Date: Wed, 28 Aug 2013 13:52:18 +0200 In-Reply-To: <87ioyq11kh.fsf@blackfin.pond.sub.org> References: <1377631034-24409-1-git-send-email-bsd@redhat.com> <87bo4igou0.fsf@blackfin.pond.sub.org> <1377689622.20403.64.camel@nilsson.home.kraxel.org> <87ioyq11kh.fsf@blackfin.pond.sub.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/2] Make mixer emulation configurable at runtime List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Bandan Das , qemu-devel@nongnu.org Hi, > >> 2. Why do we bother providing these devices when CONFIG_MIXEMU off? > >> > >> Why would anyone want hda audio devices without a mixer? Why > >> wouldn't anyone who wants hda audio devices also want CONFIG_MIXEMU > >> enabled? > > > > It'll actually work just fine with HDA. The guest figures there is no > > volume control and will fallback to do volume control in software then. > > Net effect is that the audio sample processing to change volume is done > > by the guest instead of mixemu, so you don't actually save cpu time by > > turning off mixemu ... > > I don't doubt it works, I doubt anybody would want the software mixing > done in the guest instead of mixemu so badly that he wants to use a > special device that makes that possible. Backward compatibility is the only reason. > > I think AC97 has broken volume control with CONFIG_MIXEMU=n, because the > > guest tries to use the non-functional volume controls. > > > > So, yes, for serious sound support you want CONFIG_MIXEMU=y. > > Which brings me back to question 1: why is non-serious sound support the > default? Last attempt to flip the default was vetoed by malc. cheers, Gerd