From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36209) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UJ00t-0001NO-Or for qemu-devel@nongnu.org; Fri, 22 Mar 2013 07:20:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UJ00o-0008A4-5G for qemu-devel@nongnu.org; Fri, 22 Mar 2013 07:19:59 -0400 Received: from mail-la0-x234.google.com ([2a00:1450:4010:c03::234]:62319) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UJ00n-000894-Ut for qemu-devel@nongnu.org; Fri, 22 Mar 2013 07:19:54 -0400 Received: by mail-la0-f52.google.com with SMTP id fs12so6909833lab.25 for ; Fri, 22 Mar 2013 04:19:52 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <87ppys6267.fsf@codemonkey.ws> References: <1363772625-9182-1-git-send-email-kraxel@redhat.com> <1363772625-9182-23-git-send-email-kraxel@redhat.com> <514ABC48.4070606@redhat.com> <514ACA0B.7030706@redhat.com> <514B1C76.4020400@redhat.com> <87ppys6267.fsf@codemonkey.ws> From: Peter Maydell Date: Fri, 22 Mar 2013 11:19:32 +0000 Message-ID: Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [PATCH 22/23] gtk: show a window for each graphical QemuConsole List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Gerd Hoffmann , qemu-devel@nongnu.org On 21 March 2013 18:25, Anthony Liguori wrote: > Gerd Hoffmann writes: >> I think the most sensible way to handle this is to implement the output >> routing device, make it own the (single) QemuConsole, and depending on >> the router state the one or the other display device is allowed to >> render to the QemuConsole. > > Where does the switching happen in hardware? Is this two devices with a > DVI port with a switch on it to have a single output port or it is > something more sophisticated where there are two memory regions and a > register is used to select which one is written out? The motherboard has a DVI multiplexer, which selects between the two video+audio output streams (actually it selects between three sources but we don't model the second daughterboard at all). I think these streams are not actually DVI but they are certainly video with pixel clock and S/PDIF audio already. There's a config register in the motherboard which selects which source should go out to the DVI connector. Conceptually I think it should look like this: /-----\ [ PL111 ] ===(video)====> | | | MUX | ===(video)===> [display] [ PL111 ] ===(video)====> | | \-----/ ^ [arm_sysregs]---(qemu_irq)---/ (where [] means a device and () a kind of connection.) If we supported routing of audio output we could in theory run the audio through the mux in the same way. -- PMM