[PATCH xserver] Pass ClientPtr to FlushCallback

[Michel Dänzer]

On 03.08.2016 09:40, Eric Anholt wrote:
> Michel Dänzer <michel at daenzer.net> writes:
> 
>> From: Michel Dänzer <michel.daenzer at amd.com>
>>
>> This change has two effects:
>>
>> 1. Only calls FlushCallbacks when we're actually flushing data to a
>>    client. The unnecessary FlushCallback calls could cause significant
>>    performance degradation with compositing, which is significantly
>>    reduced even without any driver changes.
>>
>> 2. By passing the ClientPtr to FlushCallbacks, drivers can completely
>>    eliminate unnecessary flushing of GPU commands by keeping track of
>>    whether we're flushing any XDamageNotify events to the client for
>>    which the corresponding rendering commands haven't been flushed to
>>    the GPU yet.
>>
>> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
>> ---
>>
>> See https://lists.freedesktop.org/archives/amd-gfx/2016-August/000977.html
>> for an example of how to take advantage of this change to eliminate
>> unnecessary GPU flushes.
> 
> Note: Mesa's DRI2 is (supposed to be) doing XSync() during glXWaitX() to
> ensure that the server has processed the client's X requests and flushed
> its batchbuffers, so that the kernel serializes the batchbuffer from X
> before the next rendering by Mesa.  I think your xf86-video-ati patches
> will break that.

Can you elaborate how? I honestly can't imagine.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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