Re: [Qemu-devel] [PATCH 3/8] console: add qemu_alloc_display_format.

[Frederic Konrad]

On 18/05/2015 13:17, Gerd Hoffmann wrote:
> On Mo, 2015-05-18 at 09:51 +0200, Frederic Konrad wrote:
> > On 18/05/2015 09:34, Gerd Hoffmann wrote:
> > > On Mi, 2015-05-13 at 21:12 +0200, address@hidden wrote:
> > > > From: KONRAD Frederic <address@hidden>
> > > >
> > > > This allows to create a surface with a different format than xrgb8888.
> > > What is the use case for this?
> > >
> > > cheers,
> > >     Gerd
> > Hi,
> >
> > The Display Port introduced in patch 7 and the driver use differents
> > pixel format.
> > eg: rgb565, RGB888, etc. see xilinx_dp_change_graphic_fmt in patch 7:
> Ah, and dpdma scatterlists (patch 6) suggest the guest framebuffer is
> not contiguous in guest phyiscal memory, correct?  So using guest memory
> as surface storage using qemu_create_displaysurface_from() doesn't work.
Exactly, the framebuffer is not necessarilly contiguous, so I need to 
put the
fragment into the pixman storage.

> But I think you can simply call qemu_create_displaysurface_from() with
> linesize=0 and data=NULL to make pixman allocate storage for you.
Ah, maybe! I'll check that.

Thanks,
Fred
> cheers,
>    Gerd