From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59646) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Su12s-0004yW-Jc for qemu-devel@nongnu.org; Wed, 25 Jul 2012 08:50:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Su12q-0006qg-B1 for qemu-devel@nongnu.org; Wed, 25 Jul 2012 08:50:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:29089) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Su12q-0006qS-2V for qemu-devel@nongnu.org; Wed, 25 Jul 2012 08:50:28 -0400 Message-ID: <500FEB84.6040409@redhat.com> Date: Wed, 25 Jul 2012 15:50:12 +0300 From: Avi Kivity MIME-Version: 1.0 References: <20120706092054.32044.37307.malonedeb@wampee.canonical.com> <20120725082553.26838.91137.malone@chaenomeles.canonical.com> <500FC6D2.2080000@msgid.tls.msk.ru> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Bug 1021649] Re: qemu 1.1.0 waits for a keypress at boot List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefano Stabellini Cc: Michael Tokarev , "qemu-devel@nongnu.org" , Paul Brook On 07/25/2012 02:12 PM, Stefano Stabellini wrote: > On Wed, 25 Jul 2012, Michael Tokarev wrote: >> Stefano, Paul, can you take a look please? >> >> https://bugs.launchpad.net/bugs/1021649 > > That is a very good bug triage that you did! > > However "main_loop_wait: block indefinitely" only increases the maximum > select timeout of QEMU's main_loop. > That mean that if one or more emulators have bugs and don't get > notifications correctly they might hang. > The reason why it only reproduces with nographic is that both sdl and vnc > introduce a gui_timer that wakes QEMU up every 30ms. > > So the question is: why is kernel_irqchip=on required to repro the bug? > It strikes me as a bug in kernel_irqchip that prevents QEMU from being > waken up when it should. kernel_irqchip=on means that many guest timers and interrupt sources are removed from qemu and implemented in the kernel, so qemu sees a lot less wakeups and hangs. With kernel_irqchip=off the APIC or PIT wakes up qemu, taking the place of the keypress. -- error compiling committee.c: too many arguments to function