From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:49503)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mark.cave-ayland@ilande.co.uk>) id 1Yz9u8-0004xC-Q0
	for qemu-devel@nongnu.org; Sun, 31 May 2015 16:32:21 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <mark.cave-ayland@ilande.co.uk>) id 1Yz9u5-0004Hg-L9
	for qemu-devel@nongnu.org; Sun, 31 May 2015 16:32:20 -0400
Received: from s16892447.onlinehome-server.info ([82.165.15.123]:58427)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mark.cave-ayland@ilande.co.uk>) id 1Yz9u5-0004HX-Ee
	for qemu-devel@nongnu.org; Sun, 31 May 2015 16:32:17 -0400
Message-ID: <556B6FC3.7020301@ilande.co.uk>
Date: Sun, 31 May 2015 21:32:03 +0100
From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
MIME-Version: 1.0
References: <1430152117-100558-1-git-send-email-pbonzini@redhat.com>	<1430152117-100558-4-git-send-email-pbonzini@redhat.com>	<556457F5.7050607@redhat.com>	<CAFEAcA8rX6DqBpRo3djJDCLuLAL_r=aXr-+mECgEPBo++mVk1w@mail.gmail.com>
	<55645F81.5070206@redhat.com>
In-Reply-To: <55645F81.5070206@redhat.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH 03/29] display: enable DIRTY_MEMORY_VGA
 tracking explicitly
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/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: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>, Peter Maydell <peter.maydell@linaro.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>, Fam Zheng <famz@redhat.com>, QEMU Developers <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>

On 26/05/15 12:56, Paolo Bonzini wrote:

> On 26/05/2015 13:52, Peter Maydell wrote:
>> On 26 May 2015 at 12:24, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>>> Peter, Mark, Aurelien, can you review and ack this patch?
>> Could you provide some explanation/documentation of when a
>> display device needs to set DIRTY_MEMORY_VGA (and when it
>> doesn't)?
> 
> It needs to set it if it uses memory_region_get/set/clear_dirty with
> DIRTY_MEMORY_VGA as the last argument.
> 
>> If we get it wrong is there any way to make qemu
>> assert or otherwise catch the error?
> 
> It may be possible to check against mr->dirty_log_mask in
> memory_region_get/set/clear_dirty.  However, it is just as likely to
> have some corner case that is correct but triggers the assertion.
> 
> I haven't thought much about it, because a simple grep for
> DIRTY_MEMORY_VGA will catch the device models that need care.

Hi Paolo,

Sorry for a taking a while to get around to this. I've just tested the
v3 patchset on qemu-system-sparc for both CG3 and TCX and I don't see
any display issues (or at least if this were broken I'd expect to see
missing video updates/strange video artifacts).

So while I can't comment on the specifics, it looks reasonable based
upon the patchset and doesn't break anything so:

Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>


ATB,

Mark.