[Mesa-dev] [PATCH 0/9] dri2: Swapbuffer update v3.

[Timothy Arceri]

On 05/09/18 23:36, Thomas Hellstrom wrote:
> On 09/05/2018 02:36 PM, Timothy Arceri wrote:
>> On 05/09/18 22:09, Thomas Hellstrom wrote:
>>> On 09/05/2018 01:45 PM, Timothy Arceri wrote:
>>>>
>>>>
>>>> On 16/08/17 04:31, Thomas Hellstrom wrote:
>>>>> Implement back-to-fake-front flips,
>>>>> Fix EGL_BUFFER_PRESERVED path.
>>>>> Implement dri3 support for GLX_SWAP_EXCHANGE_OML and 
>>>>> GLX_SWAP_COPY_OML.
>>>>>
>>>>> The back-to-fake-front flips will save a full buffer copy in the 
>>>>> case of a
>>>>> fake front being enabled and GLX_SWAP_UNDEFINED_OML.
>>>>>
>>>>> Support for EGL_BUFFER_PRESERVED and GLX_SWAP_X_OML are mostly 
>>>>> useful for
>>>>> things like glretrace if traces are capured with applications 
>>>>> relying on a
>>>>> specific swapbuffer behavior.
>>>>>
>>>>> The EGL_BUFFER_PRESERVED path previously made sure the present was 
>>>>> done as
>>>>> a copy, but there was nothing making sure that after the present,
>>>>> the same back buffer was chosen.
>>>>> This has now been changed so that if the previous back buffer is
>>>>> idle, we reuse it. Otherwise we grab a new and copy the contents and
>>>>> buffer age from the previous back buffer. Server side flips are 
>>>>> allowed.
>>>>>
>>>>> GLX_SWAP_COPY_OML will behave like EGL_BUFFER_PRESERVED.
>>>>>
>>>>> GLX_SWAP_EXCHANGE_OML will behave similarly, except that we try to 
>>>>> reuse the
>>>>> previous fake front as the new back buffer if it's idle. If not, we 
>>>>> grab
>>>>> a new back buffer and copy the contents and buffer age from the old 
>>>>> fake front.
>>>>>
>>>>> v2:
>>>>> - Split the original patch,
>>>>> - Make sure we have a context for blitImage even if we don't have a
>>>>> current context.
>>>>> - Make sure the delayed backbuffer allocation is performed before
>>>>> glXSwapBuffers, glXCopyBuffers and querying buffer age.
>>>>> v3:
>>>>> - squash three patches related to the same change.
>>>>> - Address review comments by Michel Dänzer.
>>>>>
>>>>> Testing done:
>>>>> piglit tests/quick without regressions on svga.
>>>>> A modified piglit glx-swap-exchange posted for review on the piglit 
>>>>> list.
>>>>> That test required modifying the dri2 state tracke to advertise 
>>>>> unconditional
>>>>> support for GLX_SWAP_EXCHANGE_OML
>>>>
>>>> What exactly do I need to do to force this to be advertised? A 
>>>> bigger question is what more is required to expose 
>>>> GLX_SWAP_EXCHANGE_OML more generally?
>>>>
>>>> It seems this is required for a few games running on wine [1].
>>>>
>>>> [1] 
>>>> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugs.freedesktop.org%2Fshow_bug.cgi%3Fid%3D97516&data=02%7C01%7Cthellstrom%40vmware.com%7Cc71a9d949e56467614c108d6132c3212%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C1%7C0%7C636717488813233512&sdata=%2FmIsVYyD7Uvg2DwynXKJS3Am%2FEKiyBVz1d%2BSwjIq2Jw%3D&reserved=0 
>>>>
>>>>
>>>>
>>>
>>> You need to get the X server AIGLX to advertize it, because the 
>>> available features are the intersection of the X server AIGLX 
>>> features and the dri driver features, even if this is purely 
>>> implemented in the dri client. The reason GLX works this way is that 
>>> after you've choosen your config you can either choose to select a 
>>> direct or indirect context. That was a poor design.
>>>
>>> Now the problem is that AIGLX isn't able to support it, because it 
>>> uses the dri driver dri2 path rather than the dri3 path, and I never 
>>> got to modifying AIGLX to use the dri3 path. Didn't think it was 
>>> worth the extra work.
>>
>> Hmm ... thanks for the info. I should at least add some of this to the 
>> bug report.
>>
>>>
>>> In any case, you can hack-enable GLX_SWAP_EXCHANGE_OML if the client 
>>> is using dri3 by adding __DRI_ATTRIB_SWAP_EXCHANGE to 
>>> back_buffer_modes[] in src/gallium/state_trackers/dri/dri_screen.c, 
>>> recompile and make sure the X server also picks up the recompiled 
>>> driver. That is if you have a gallium driver. This worked fine with 
>>> vmwgfx at the time I pushed the patch as tested by the corresponding 
>>> piglit test.
>>
>> I did try this already with radeonsi but it didn't seem to work. I 
>> even restarted my PC to make sure the correct driver was selected.
> 
> How did you test? I'll give it a test on vmwgfx + piglit.
> /Thomas

I just tried running the glx-swap-exchange piglit test. I was still getting:

Couldn't get a GLX_SWAP_EXCHANGE_OML, RGBA, double-buffered fbconfig
PIGLIT: {"result": "skip" }


> 
> 
>>
>>>
>>> For the other dri drivers there should be a similar way to set the 
>>> back_buffer_modes[].
>>>
>>> Thanks,
>>> Thomas
>>>
>>>>> A piglit glx-swap-copy test derived from the glx-swap-exchange test.
>>>>> Not posted yet.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> mesa-dev mailing list
>>>>> mesa-dev at lists.freedesktop.org
>>>>> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fmesa-dev&data=02%7C01%7Cthellstrom%40vmware.com%7Cc71a9d949e56467614c108d6132c3212%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C1%7C0%7C636717488813243551&sdata=iG47YiO49K4vh1C0aV5SiSX%2BlthujiFPXro5DiDNInY%3D&reserved=0 
>>>>>
>>>>>
>>>
>