From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=37175 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1PerXx-0004Fy-2W
	for qemu-devel@nongnu.org; Mon, 17 Jan 2011 11:03:10 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <jan.kiszka@siemens.com>) id 1PerXu-0004MG-RJ
	for qemu-devel@nongnu.org; Mon, 17 Jan 2011 11:03:07 -0500
Received: from goliath.siemens.de ([192.35.17.28]:22048)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <jan.kiszka@siemens.com>) id 1PerXu-0004Ly-D2
	for qemu-devel@nongnu.org; Mon, 17 Jan 2011 11:03:06 -0500
Message-ID: <4D346834.8000903@siemens.com>
Date: Mon, 17 Jan 2011 17:03:00 +0100
From: Jan Kiszka <jan.kiszka@siemens.com>
MIME-Version: 1.0
References: <1292879604-22268-1-git-send-email-agraf@suse.de>
	<1292879604-22268-9-git-send-email-agraf@suse.de>
	<4D34542D.7080301@siemens.com> <4D3467B9.3070207@suse.de>
In-Reply-To: <4D3467B9.3070207@suse.de>
Content-Type: text/plain; charset=ISO-8859-15
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: [PATCH 8/8] ahci: fix !msi interrupts
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.nongnu.org/archive/html/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: Alexander Graf <agraf@suse.de>
Cc: Kevin Wolf <kwolf@redhat.com>, Joerg Roedel <Joerg.Roedel@amd.com>, Sebastian Herbszt <herbszt@gmx.de>, qemu-devel Developers <qemu-devel@nongnu.org>, Gerd Hoffmann <kraxel@redhat.com>

On 2011-01-17 17:00, Alexander Graf wrote:
> Jan Kiszka wrote:
>> On 2010-12-20 22:13, Alexander Graf wrote:
>>   
>>> When not using MSI, receiving an interrupt while the interrupt line is active
>>> pulses the interrupt line. Without this, guests don't realize that a new
>>> interrupt occured.
>>>     
>>
>> This doesn't look OK. The device model should look at the currently used
>> mode and switch between edge and level triggering accordingly. As it
>> appears like this is what it already does, this change may just paper
>> over the real issue.
>>   
> 
> Well, I have this internal abstraction to make edge and level triggered
> interrupt triggering easier. irq_lower is a simple nop for the edge case.
> 

I'm concerned about the artificial edge you generate for the level
triggered case. That's not like real hw behaves. If you need it,
something else might still be broken.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux