From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1M1yiE-0003Qv-2p for qemu-devel@nongnu.org; Thu, 07 May 2009 04:12:14 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1M1yi8-0003Fg-Dh for Qemu-devel@nongnu.org; Thu, 07 May 2009 04:12:12 -0400 Received: from [199.232.76.173] (port=39804 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1M1yi8-0003FF-69 for Qemu-devel@nongnu.org; Thu, 07 May 2009 04:12:08 -0400 Received: from lizzard.sbs.de ([194.138.37.39]:15827) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1M1yi7-0000FP-I0 for Qemu-devel@nongnu.org; Thu, 07 May 2009 04:12:07 -0400 Message-ID: <4A0297D2.4040009@siemens.com> Date: Thu, 07 May 2009 10:12:02 +0200 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: Question about KVM and PC speaker 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> <49FF1919.1030909@gmx.de> <49FF5033.1050402@web.de> <20090504205618.GP5889@const.famille.thibault.fr> <49FF5777.8070704@web.de> <4A006268.6040006@linux-fuer-blinde.de> <3D0ED7CD58CF4D37904670A5A85AE2C7@FSCPC> <4A0167B7.2050200@siemens.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Sebastian Herbszt Cc: Qemu-devel@nongnu.org, kvm@vger.kernel.org, Simon Bienlein Sebastian Herbszt wrote: > Jan Kiszka wrote: >> Sebastian Herbszt wrote: >>> Simon Bienlein wrote: >>>> Is a support for BIOS worked on right now? >>> >>> The vgabios (vgabios.c) has a "FIXME should beep". Volker, do you plan >>> to fix this? >>> >>> Which frequency should be used for the beep? Which delay? >> >> I would try 1 KHz and some hundred milliseconds. > > I just looked at some vga bios and it uses about 896,45 Hz. > >>> Getting a delay using "inb(0x61) & 0x10" is still a no go on qemu, >>> right? >> >> Looks like (should be far too inaccurate for longer delays). What about >> 0x40:0x6c, the BIOS' daily timer counter? > > The bios i looked at used the refresh request port 0x61. This is > supported by bochs and > there is also a patch for qemu to replace the dummy [1]. The rombios > uses this to provide > INT 15h AH=86h functionality; this is likely broken with the dummy code > in qemu. I see no problem with improving qemu's emulation accuracy this way a bit. But I wouldn't built new delay implementations on top of it, specifically if the code is in fact aware of running over a hypervisor. Such micro-timings are far too inaccurate for longer delays in an environment where you cannot be sure of running all the time during that period. > > Anyway, using "timer ticks since midnight" should be possible (INT 08h > handler is set up > before vga bios is called). > > [1] http://article.gmane.org/gmane.comp.emulators.bochs.devel/7594 > > - Sebastian > Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux