From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:33276) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RzkxC-0000XA-0B for qemu-devel@nongnu.org; Tue, 21 Feb 2012 03:20:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Rzkx4-0003t6-V8 for qemu-devel@nongnu.org; Tue, 21 Feb 2012 03:20:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24130) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rzkx4-0003sh-Ob for qemu-devel@nongnu.org; Tue, 21 Feb 2012 03:19:58 -0500 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 q1L8JuAm005524 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 21 Feb 2012 03:19:56 -0500 Date: Tue, 21 Feb 2012 10:19:48 +0200 From: Alon Levy Message-ID: <20120221081948.GC6476@garlic> References: <1329686886-6853-1-git-send-email-alevy@redhat.com> <1329686886-6853-6-git-send-email-alevy@redhat.com> <4F422F5C.9060202@redhat.com> <4F42BB27.6070504@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F42BB27.6070504@redhat.com> Subject: Re: [Qemu-devel] [RFC 5/7] qxl-render: call ppm_save on callback List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: Luiz Capitulino , Gerd Hoffmann , elmarco@redhat.com, qemu-devel@nongnu.org On Mon, Feb 20, 2012 at 02:29:11PM -0700, Eric Blake wrote: > On 02/20/2012 04:32 AM, Gerd Hoffmann wrote: > > Hmm, that is pretty lame. There are users like autotest which expect > > the screen dump being there when the monitor command is finished, that > > change will break them. > > Libvirt is another such user. > > > > > Unfortunaly there is no easy way out. I think the options are: > > > > (1) Keep existing behavior. That means the screenshot might show old > > screen content. Not very nice too. Would work sort-of ok for > > autotest though as autotest does screenshots every second and thus > > the screen content wouldn't be older than a second. > > > > (2) Async monitor command. Keeps interface and works nicely. A bunch > > of QAPI bits tickled into master meanwhile, so we could look at > > this again. Luiz? What is the status here? > > > > (3) Something like this patch + additionally introduce a > > "your-screenshot-is-finished-now" qmp event. Will break existing > > users too. But at least they can be adapted without requiring > > some external, nonportable service like inotify ... > > Libvirt would want 3) - any command that becomes async also needs an > event to tell us when the command is completed, so that libvirt can > maintain the synchronous interface to the user (and/or expose a new flag > to allow the user to also benefit from the asynchronous command). If I do 2) then libvirt won't notice because the monitor command will block as usual. Only change would be internal, qemu would continue processing other fds in the interim. > > -- > Eric Blake eblake@redhat.com +1-919-301-3266 > Libvirt virtualization library http://libvirt.org >