Jason BARSTOW wrote:
> 
> 
> 
>>> Each user (process) instance of dfb has its own system/gfxdriver
> backend.
>>> In a multi-app build, the first instance becomes the master instance and
>>> all subsequent become slaves.
>>> If we consider a normal system/gfxdriver set up -
>>>       - each instance maps the whole framebuffer into its own process
>>> space.
>>>       - each instance has its own set of MMIO registers of accelerated
>>> graphic ops.
> 
>> Correct.
> 
>>>       - allocations of surfaces are marshalled via the master instance.
> 
>> The surface manager code runs in any process. Only the destructor
>> of surface objects in executed in the master.
> 
> Doesn't construction also execute in master - or at least require some form
> of mutexing?
> Otherwise, what prevents two processes allocating the same video memory to
> two surfaces?

Construction takes place in any process. There's a surface manager lock.

-- 
Best regards,
   Denis Oliver Kropp

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| DirectFB - Hardware accelerated graphics |
| http://www.directfb.org/                 |
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