linux-kernel - Re: [PATCH 0/2] drm/vkms: Bugfix for igt-tests

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Message-ID: <CAKkTe8GsZkBhLLE=Z-JaCpErhi5VvcadTmsw3Wh25Kg5U+VbCA@mail.gmail.com>
Date:   Fri, 1 Feb 2019 21:25:38 -0200
From:   Shayenne Moura <shayenneluzmoura@...il.com>
To:     Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>,
        Haneen Mohammed <hamohammed.sa@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>
Cc:     dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/2] drm/vkms: Bugfix for igt-tests

Daniel Vetter and I were discussing about this solution. We figured out that
after these patches, tests were passing but when the computer has a heavy
background workload, tests fail.

I tried a new solution. Instead of change the vblank_time variable, make the
`get_vblank_timestamp` return false when is not happening a vblank_irq.

It worked in the same way of our last attempt.

The reason for this change is that, when the timestamp is not accurate,
drm_vblank deals with this correcting timestamp when `get_vblank_timestamp`
returns false. However, this requirement is important when real hardware has an
error, and could not return the accurate vblank. Now, we need to know if our
`vkms_get_vblank_timestamp` should return false and when.

Em qua, 30 de jan de 2019 às 14:05, Shayenne Moura
<shayenneluzmoura@...il.com> escreveu:
>
> This patchset contains patches to fix the extra frame bug on kms_flip
> igt-test. First patch solves the extra vblank frame that breaks many
> tests on kms_flip and second patch solves the race condition caused
> by the solution added in the first one.
>
> Shayenne Moura (2):
>   drm/vkms: Bugfix extra vblank frame
>   drm/vkms: Bugfix racing hrtimer vblank handle
>
>  drivers/gpu/drm/vkms/vkms_crtc.c | 21 +++++++++------------
>  1 file changed, 9 insertions(+), 12 deletions(-)
>
> --
> 2.17.1
>