From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:60958) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TLF6I-0001cX-7T for qemu-devel@nongnu.org; Mon, 08 Oct 2012 11:18:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TLF6C-0003mi-Px for qemu-devel@nongnu.org; Mon, 08 Oct 2012 11:18:34 -0400 Received: from mail-da0-f45.google.com ([209.85.210.45]:35489) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TLF6C-0003m2-IV for qemu-devel@nongnu.org; Mon, 08 Oct 2012 11:18:28 -0400 Received: by mail-da0-f45.google.com with SMTP id n15so1631958dad.4 for ; Mon, 08 Oct 2012 08:18:26 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <5072EEB7.2070408@redhat.com> Date: Mon, 08 Oct 2012 17:18:15 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <506F1934.5000002@siemens.com> <506F207A.70805@siemens.com> <5072782E.9090707@siemens.com> In-Reply-To: <5072782E.9090707@siemens.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] versatile: Push lsi initialization to the end List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Peter Maydell , qemu-devel Il 08/10/2012 08:52, Jan Kiszka ha scritto: > On 2012-10-06 04:13, Peter Maydell wrote: >> On 5 October 2012 19:01, Jan Kiszka wrote: >>> I'm not a fan of this either, but the alternatives are way more >>> complicated. We either need to rewrite the chardev subsystem, >>> specifically how mux'ed devices are registered and how the active one is >>> selected. Or we need to avoid flushing "unrelated" BHs for block >>> devices. Not sure of those read requests can be postponed. >> >> Is this a regression? If it is then the obvious answer is to back >> out whatever broke it... > > I'm using this machine for the first time, so I cannot answer this from > the top of my head. However, I don't think it can be a regression. > > Mux chardevs work like this: You create the backend, then you register > the frontend with them, one by one. The last one registered is the first > one active. It should also receive the open event of chardev. But as > that open even is issued via a BH and last frontend, the serial device, > arrives after the first BH flushing, things break. Does something like this work instead? diff --git a/qemu-char.c b/qemu-char.c index b082bae..1ed6d49 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -465,6 +465,9 @@ static void mux_chr_update_read_handler(CharDriverState *chr) d->focus = d->mux_cnt; d->mux_cnt++; mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_IN); + if (chr->opened) { + mux_chr_send_event(d, d->focus, CHR_EVENT_OPENED); + } } static CharDriverState *qemu_chr_open_mux(CharDriverState *drv) Paolo