From mboxrd@z Thu Jan 1 00:00:00 1970 From: Samuel Thibault Subject: Re: Xen frame buffer related Date: Fri, 4 Apr 2008 16:40:53 +0200 Message-ID: <20080404144053.GE4075@implementation> References: <46009afb0804030657rd1c2443jc3d4406235633417@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <46009afb0804030657rd1c2443jc3d4406235633417@mail.gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Dushmanta Mohapatra Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Hello, Dushmanta Mohapatra, le Thu 03 Apr 2008 09:57:11 -0400, a écrit : > I see two xenfb.c files in the Xen (3.2) source. One in tools/ioemu/hw/ and the > other in linux-2.6.18-xen.hg/drivers > /xen/fbfront/. So I think the first one is the userspace-backend and the second > one is the kernel-space front-end. That's it. > I do not understand why originally the > back-end was not made a part of kernel like other devices? Why should it be? In the case of PVFB, he backend is responsible for actually showing the frame buffer. A userspace X11 application or VNC server is thus the logical way. > Also could you please tell me how to use this backend userspace tool. You just need to add vfb = [ 'type=sdl' ] if you want to have an SDL window showing up when you start your domain, or vfb = [ 'type=vnc' ] if you want to have a VNC server started instead. > If I have understood it correctly then in Xen 3.1, this back end tool uses > VNCServer for displaying the contents of Frontend frambuffer. So what has > changed with the use of QEMU. There is now the SDL choice. > Finally just to give you an idea about my project: Lets suppose a domU gets > migrated from a Physical machine having a display of X1xY1 to another physical > machine having a display of X2xY2. In the unstable tree, there is an OpenGL rendering which can accomodate with this by rescaling the frame buffer. > Also a similar example can be a domU getting migrated from a machine > having one type of keyboard to a machine having another type of > keyboard. Mmm, you may have a problem here, because PVFB uses Linux keycodes, not keysyms. I.e. whatever the configuration of the host machine, the guest keyboard configuration will be used. > If I see Xen > 3.2 code in the user space backend framebuffer code (/tools/ioemu/hw/xenfb.c) I > see functions like "static int xenfb_read_frontend_fb_config(struct xenfb > *xenfb)" and "static int xenfb_read_frontend_kbd_config(struct xenfb *xenfb)". That's to get the initial size, but in the unstable tree we now have a PVFB event that permits the guest to change the size dynamically. Samuel