WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Dynamic modes in PV xenfb?

To: "Pat Campbell" <plc@xxxxxxxxxx>
Subject: Re: [Xen-devel] Dynamic modes in PV xenfb?
From: Markus Armbruster <armbru@xxxxxxxxxx>
Date: Thu, 22 Nov 2007 16:39:09 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Thu, 22 Nov 2007 07:39:48 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <47440E7F.3E48.0018.0@xxxxxxxxxx> (Pat Campbell's message of "Wed\, 21 Nov 2007 10\:57\:50 -0700")
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <1195667190.1701.192.camel@bling> <47440E7F.3E48.0018.0@xxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux)
"Pat Campbell" <plc@xxxxxxxxxx> writes:

> Hi,
>
> At http://wiki.xensource.com/xenwiki/VirtualFramebuffer in Stage 2 adding 
> dynamic modes to the Xen VirtualFramebuffer is mentioned.
>
> Does not appear this was ever done.  Is there a technical reason this has not 
> been implemented or just a case of not enough time or interest?
>
> If it is technically feasible do you have any pointers or examples on how to
> go about implementing this feature?
>
> Thanks in advance.
>
> Pat

The protocol between frontend and backend is easy enough to extend in
a backward compatible manner, so negotiating resolution changes
shouldn't be hard.  Guard the extension with suitable flags in
xenstore (feature-FOO to offer FOO, request-FOO to take it, see source
code for examples).

The frontend exposes the framebuffer to the backend in a rather
archaic manner.  The size of the page directory artificially limits
the framebuffer to 4M.  Fixable, but I'd rather see this converted to
grant tables (assuming they can support large grants now).

>From a usability point of view, you should be able to resize the pvfb
window like any other window.  But then the backend initiates the
resize.  I don't know whether software running in the frontend is fine
with framebuffers initiating resolutions changes.

Please let me know if you tackle this feature.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>