Re: libxl videoram for cirrus graphics

[Ian Campbell <ian.campbell@citrix.com>]

On Tue, 2013-09-17 at 14:24 +0100, Wei Liu wrote:
> On Tue, Sep 17, 2013 at 12:54:57PM +0000, Rob Hoes wrote:
> > Hi,
> > 
> > The videoram setting in xl config files is documented as follows:
> > 
> > "
> > videoram=MBYTES
> > 
> >     Sets the amount of RAM which the emulated video card will contain, which in turn limits the resolutions and bit depths which will be available. The default amount of video ram for stdvga is 8MB which is sufficient for e.g. 1600x1200 at 32bpp and videoram option is currently working only when using the qemu-xen-traditional device-model.
> > 
> >     When using the emulated Cirrus graphics card (vga="cirrus") the amount of video ram is fixed at 4MB which is sufficient for 1024x768 at 32 bpp and videoram option is currently working only when using the upstream qemu-xen device-model.
> > "
> > 
> > XenServer also uses a default of 4MB video ram for cirrus graphics.
> > 
> > However, when I use xl to create a VM with cirrus graphics, I get 8MB of video RAM by default. Moreover, setting it to videoram=4 in the config file leads to complaints from libxl:
> > 
> >     libxl_create.c:228:libxl__domain_build_info_setdefault: videoram must be at least 8 mb
> > 
> > Is there a bug in the logic in libxl_create.c?
> > 
> 
> I think the document needs to be updated.
> 
> commit 2e814a017155b885e4d4b5a88dc05e7367a9722a
> Author: Fabio Fantoni <fabio.fantoni@heliman.it>
> Date:   Fri Feb 15 13:32:27 2013 +0000
> 
>     tools/libxl: Improve videoram setting
>     
>     - If videoram setting is less than 8 mb shows error and exit.

I wonder why this is the case. Fabvio do you remmeberwhere this number
8M came from for Cirrus?