[igt-dev] [PATCH i-g-t v3 4/4] tests/kms_frontbuffer_tracking: Remove redundant modesets during subtest start.

[Maarten Lankhorst]

Op 05-04-18 om 18:31 schreef Paulo Zanoni:
> Em Qua, 2018-03-21 às 12:47 -0700, Paulo Zanoni escreveu:
>> Em Qui, 2018-03-01 às 16:33 +0100, Maarten Lankhorst escreveu:
>>> Hey,
>>>
>>> Op 27-02-18 om 09:52 schreef Maarten Lankhorst:
>>>> CRC capturing enables the display, then disables it again. With
>>>> igt_display we can use igt_display_reset to restore the original
>>>> state,
>>>> without committing it to the hw.
>>>>
>>>> All subtests first set their own state anyway, so we can save up
>>>> on
>>>> the number of commits.
>>> I patched igt_kms to report the number of modesets..
>>>
>>> Without this patch running ./kms_frontbuffer_tracking on a 2 output
>>> system (f2-snb-2600, forced VGA-1 enabled):
>>> Performed 382 modesets
>>>
>>> With this patch on a 2 output system:
>>> Performed 23 modesets
>>>
>>> On geminilake this means we save a lot of time, so could someone
>>> review this series?
>> Is there an analysis on how reducing the amount of modesets will
>> *not*
>> invalidade the purpose of the tests? The modesets are there for a
>> reason.
> Ping?
How will doing a modeset improve the test?

We preserve the mode only if it makes sense, each subtest sets the parameters it wants. It just happens that in most cases that's the same mode, so we don't have to do a modeset.
That's all. :)

~Maarten