[Mesa-dev] very strange intermittent frame-dropping

[Luke Kenneth Casson Leighton]

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.
---
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Wed, Apr 5, 2017 at 1:31 PM, Eero Tamminen <eero.t.tamminen at intel.com> wrote:
> Hi,
>
> On 04.04.2017 14:10, Luke Kenneth Casson Leighton wrote:
>>
>> On Tue, Apr 4, 2017 at 11:04 AM, Eero Tamminen
>> <eero.t.tamminen at intel.com> wrote:
>>>>
>>>> anyway, apologies: nobody whose applications are affected by this
>>>> really has a clue where the *actual* bug is so i am escalating it down
>>>> the chain of library dependencies, making people aware.  it could be
>>>> X11, it could be mesa, we just don't know.
>>>
>>>
>>>
>>> Does it happen only with the old, non-compositing window managers like
>>> FVWM2, or also with something newer?
>>
>>
>>  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?

>> 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

 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.

l.