[Spice-devel] A question about QXL

[Uri Lublin]

On 10/31/2016 11:57 AM, Frediano Ziglio wrote:
>>
>> Hi experts,
>>
>>   Recently I’m studying QXL XDDM driver to see how the display are
>>   accelerated.
>>
>>   One thing I do not understand is that I thought some updates should be
>>   missing on clients.
>>   Say in the implementation of DrvBitBlt function, if it is not supported.
>>   the implemention will punt to EngBitBlt.
>>
>>   However, in such case, no QXL command is pushed to cmd ring. So how does
>>   spice client notice the frame buffer change
>> made by EngBitBlt?
>>
>>   Can anyone help provide guidance on this?
>>
>>   Thanks.
>
> Hi,
>   basically when EngBitBlt is called Windows implements the command
> using different calls so basically EngBitBlt will call others Drv* functions
> to implement DrvBitBlt for QXL driver. That Drv* functions will push commands
> to the ring.


"Different calls" -- look at
   DodPresentDisplayOnly and DodSystemDisplayWrite

Uri