[Mesa-dev] very strange intermittent frame-dropping

[Eero Tamminen]

Hi,

On 06.04.2017 00:36, Luke Kenneth Casson Leighton wrote:
> eero, apologies, the mesa-dev list's traffic is very high, i'll switch
> over to digest, so please do cc me each time, to mitigate that.

OK.


>>>  there's a whole stack of people reporting this occurring, running the
>>> full range of window managers.
>>>
>>>> Does DRI2 vs. DRI3 have any effect on it?
>>>
>>>  hmm, good question.  i'm running with "DRI" "true"
>>
>> Valid values for "DRI" setting are "2" or "3".
>>
>>> (so don't know if it's 2 or 3),
>>
>> This tells you which version apps get:
>>         LIBGL_DEBUG=verbose glxgears
>
>  LIBGL_DEBUG=verbose glxgears
> libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/tls/i965_dri.so
> libGL: OpenDriver: trying /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
> libGL: Can't open configuration file /home/lkcl/.drirc: No such file
> or directory.
> libGL: Using DRI2 for screen 0
> libGL: Can't open configuration file /home/lkcl/.drirc: No such file
> or directory.
> Running synchronized to the vertical refresh.  The framerate should be
> approximately the same as the monitor refresh rate.
> 303 frames in 5.0 seconds = 60.424 FPS
> 212 frames in 11.7 seconds = 18.079 FPS
>
> huh.  so i _thought_ it was going to be DRI3.   that's supposed to be
> the default, isn't it?

You need it enabled in Intel DDX build, in X configuration, and Mesa 
build (with building done with suitable deps present).

On normal distros, support should be built in, but not necessarily 
enabled for run-time by default.  In your own builds you need to make 
sure you enable support for DRI3 (= use "--enable-dri3" configure option).


>>> other people will have different settings.
>>
>>
>> It would be interesting to know whether there's any correspondence with the
>> DRI setting, and what exact Mesa & X versions they have.
>
>  looks like i'm on debian 13.0.6-1

???

$ cat /etc/debian_version


>  eeee this is gonna be fun - i'll relay the request and get back to
> you: might take a while, there's lots of people / lots of different
> projects.
>
>  some people are *not* able to repro the problem which is a good datapoint.


	- Eero