Re: [igt-dev] [PATCH i-g-t] tests/kms_plane: survive cdclk caused modeset

[Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>]

On 7.4.2020 19.22, Juha-Pekka Heikkila wrote:
> On 7.4.2020 19.08, Ville Syrjälä wrote:
>> On Tue, Apr 07, 2020 at 06:54:09PM +0300, Juha-Pekka Heikkila wrote:
>>> On 7.4.2020 18.36, Ville Syrjälä wrote:
>>>> On Tue, Apr 07, 2020 at 02:09:04PM +0300, Juha-Pekka Heikkila wrote:
>>>>> This change will slow this test down a bit. In mid test starting
>>>>> to use higher bpp pixel format (say 64bpp) can cause modeset.
>>>>> Use blocking commit so there's wait for modeset to happen.
>>>>
>>>> We already wait for the event the next time around. So this
>>>> doesn't make sense to me.
>>>
>>> There's those logs like this
>>> https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_470/fi-icl-guc/igt@kms_plane@pixel-format-pipe-c-planes-source-clamping.html 
>>>
>>>
>>> where going to 64bpp pixel format will cause modeset and fail running
>>> test.
>>
>> Hmm. Seems we don't have drm.debug=0x10 enabled so we don't see the
>> actual debug message :( Anyways, the real bug seems to be the lack of
>> ALLOW_MODESET.
> 
> I'll try that and see how it changes situation. I originally had idea 
> modeset will block the flip and making this commit blocking would always 
> force things always into correct order as current test didn't fail every 
> time for me.

Having that commit saying

igt_display_commit_atomic(&data->display,
	DRM_MODE_ATOMIC_ALLOW_MODESET |
	DRM_MODE_ATOMIC_NONBLOCK |
	DRM_MODE_PAGE_FLIP_EVENT, NULL);

I see test failing as before so it will not alone fix this issue. On my 
ICL box the test fail maybe 1/5 times, with the patch on list it never 
failed so far.

> 
>>
>>> I was testing this on ICL and see errors randomly, on ci those
>>> seem to be less random. Making this one commit blocking will cause
>>> modeset to settle without interrupting test, at least on my ICL.
>>>
>>> If there's a way to sort those pixel formats according to bpp and start
>>> with highest there's no need for this.
>>>
>>>>
>>>>>
>>>>> Fixes: https://gitlab.freedesktop.org/drm/intel/issues/1214
>>>>> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
>>>>> ---
>>>>>    tests/kms_plane.c | 6 ++----
>>>>>    1 file changed, 2 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/tests/kms_plane.c b/tests/kms_plane.c
>>>>> index 805795cd..2324fb6e 100644
>>>>> --- a/tests/kms_plane.c
>>>>> +++ b/tests/kms_plane.c
>>>>> @@ -569,12 +569,10 @@ static void capture_format_crcs(data_t *data, 
>>>>> enum pipe pipe,
>>>>>            if (data->display.is_atomic) {
>>>>>                /*
>>>>> -             * Use non-blocking commits to allow the next fb
>>>>> -             * to be prepared in parallel while the current fb
>>>>> -             * awaits to be latched.
>>>>> +             * Use blocking commit because there maybe
>>>>> +             * modeset when going to higher bpp pixel format.
>>>>>                 */
>>>>>                igt_display_commit_atomic(&data->display,
>>>>> -                          DRM_MODE_ATOMIC_NONBLOCK |
>>>>>                              DRM_MODE_PAGE_FLIP_EVENT, NULL);
>>>>>            } else {
>>>>>                /*
>>>>> -- 
>>>>> 2.17.1
>>>>>
>>>>> _______________________________________________
>>>>> igt-dev mailing list
>>>>> igt-dev@lists.freedesktop.org
>>>>> https://lists.freedesktop.org/mailman/listinfo/igt-dev
>>>>
>>
> 

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