From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59872) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SxwUm-0004tq-HU for qemu-devel@nongnu.org; Sun, 05 Aug 2012 04:47:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SxwUl-0002QP-C8 for qemu-devel@nongnu.org; Sun, 05 Aug 2012 04:47:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31084) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SxwUl-0002QK-4J for qemu-devel@nongnu.org; Sun, 05 Aug 2012 04:47:31 -0400 Message-ID: <501E3315.6070205@redhat.com> Date: Sun, 05 Aug 2012 11:47:17 +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> <500FEB84.6040409@redhat.com> <20120804045801.GD4231@cucamonga.audible.transient.net> In-Reply-To: <20120804045801.GD4231@cucamonga.audible.transient.net> 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 , Michael Tokarev , "qemu-devel@nongnu.org" , Paul Brook On 08/04/2012 07:58 AM, Jamie Heilman wrote: > Avi Kivity wrote: >> 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. > > You're not implying the key press waking up qemu was a planned thing > are you? I am not. > Becuase it doesn't work at all when console is a -chardev pty > device. With -machine kernel_irqchip=on -display none -chardev pty,... > qemu simply hangs and consumes as much cpu as it can, attaching to the > terminal and sending data does nothing. I'd hate to think that's the > new normal. It's not. -- error compiling committee.c: too many arguments to function