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

[Frederic Konrad <fred.konrad@greensocs.com>]

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, fred.konrad@greensocs.com wrote:
>>>> From: KONRAD Frederic <fred.konrad@greensocs.com>
>>>>
>>>> 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
>
>