From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [Qemu-devel] Re: Question about KVM and PC speaker Date: Thu, 23 Apr 2009 19:42:14 +0200 Message-ID: <49F0A876.4050902@siemens.com> References: <49EF69BC.90300@gmx.de> <49F01C8D.1010203@web.de> <20090423083252.GB5277@const.bordeaux.inria.fr> <49F031C2.5000204@siemens.com> <20090423092546.GF5277@const.bordeaux.inria.fr> <49F035E7.5080906@siemens.com> <49F03A00.8060502@redhat.com> <49F0430A.8010300@siemens.com> <49F04C80.2040204@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Samuel Thibault , Simon Bienlein , Qemu-devel@nongnu.org, kvm-devel To: Avi Kivity Return-path: Received: from gecko.sbs.de ([194.138.37.40]:23657 "EHLO gecko.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752867AbZDWRnA (ORCPT ); Thu, 23 Apr 2009 13:43:00 -0400 In-Reply-To: <49F04C80.2040204@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > Jan Kiszka wrote: >> Avi Kivity wrote: >> >>> Jan Kiszka wrote: >>> >>>> Huh, it is! Then the problem is a KVM-only thing: The kernel part hooks >>>> onto those resources but doesn't communicate changes to this user space >>>> backend. >>>> >>> In this case, the -no-kvm-pit option should help. >>> >> >> Probably fine in many cases (where the PIT is no longer used anyway), >> just a bit unintuitive for users. >> > > Yes, it's only a workaround. > >> I wonder why KVM moved port 0x61 handling into kernel space at all. By >> leaving it in pcspk hands and extending the latter to sync with the >> in-kernel PIT on sample generation, this speaker regression (of >> kvm-userspace) should have been avoidable. >> > > I'd rather not have partial components in the kernel. This case is > particularly icky though. But you surely don't want to issue the sound from kernel space. Moreover, these are separate components: the PIT doesn't bother about the speaker, if it's on or off. We just need to make pcspk KVM-aware. I think I will post a patch later today. Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux