From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1MW9U8-0000u1-Ey
	for qemu-devel@nongnu.org; Wed, 29 Jul 2009 09:46:24 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1MW9U3-0000pG-HS
	for qemu-devel@nongnu.org; Wed, 29 Jul 2009 09:46:23 -0400
Received: from [199.232.76.173] (port=56001 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1MW9U2-0000p1-Vs
	for qemu-devel@nongnu.org; Wed, 29 Jul 2009 09:46:19 -0400
Received: from canardo.mork.no ([148.122.252.1]:59612)
	by monty-python.gnu.org with esmtps
	(TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60)
	(envelope-from <bjorn@mork.no>) id 1MW9Tz-0002qz-9r
	for qemu-devel@nongnu.org; Wed, 29 Jul 2009 09:46:15 -0400
From: =?utf-8?Q?Bj=C3=B8rn_Mork?= <bjorn@mork.no>
Subject: Re: [Qemu-devel] [PATCH] alsa broken when the host is suspended (or
	hibernated)
References: <1248864666-31387-1-git-send-email-bjorn@mork.no>
	<Pine.LNX.4.64.0907291551250.3728@linmac.oyster.ru>
	<87fxcf64zy.fsf@nemi.mork.no>
Date: Wed, 29 Jul 2009 15:46:01 +0200
In-Reply-To: <87fxcf64zy.fsf@nemi.mork.no> (=?utf-8?Q?=22Bj=C3=B8rn?=
	Mork"'s message of "Wed, 29 Jul 2009 14:36:01 +0200")
Message-ID: <87bpn361ra.fsf@nemi.mork.no>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: malc <av1474@comtv.ru>
Cc: qemu-devel@nongnu.org

Bj=C3=B8rn Mork <bjorn@mork.no> writes:

> I tried your modified patch with Windows XP as a client, using the
> Windows "Sound Recorder" app for testing audio capture.  I have it
> working up until the host is suspended, but cannot make it work after
> resuming.  Nothing is captured and nothing is logged to the QEMU
> monitor. The "Sound Recorder" app just sits there after pressing record,
> without ever changing the stream position from 0,00 sec.

I added a few debug printf's and found that the problem is that
alsa_get_avail() will report 0 consistently after suspend.  Thus, we end
up silently returning before ever trying to snd_pcm_readi() anything:

    avail =3D alsa_get_avail (alsa->handle);
    decr =3D audio_MIN (dead, avail);
    if (!decr) {
        return 0;
    }


I don't know how to best fix this. We probably need to add some code
triggering ESTRPIPE when the driver is suspended, even if
alsa_get_avail() returns 0.  But I hesitate, as that seems rather
inefficent just for a special case like suspend/resume.



Bj=C3=B8rn