[RFC 0/8] drm/exynos: misc fixes and more

Tobias Jakobi tjakobi at math.uni-bielefeld.de
Tue Apr 11 10:52:16 UTC 2017

Hello Inki,

please don't forget to review this series.

Also some pointers concerning the video plane flickering and the
interlacing issue would be very welcome.

Looking at the current register defines for MXR_INT_EN suggests that
there are at least three more type of interrupt available. Any chance
these could be documented? I hope to get some more insight into this
issue, which apparantly is caused by insufficient bandwidth.

For the interlacing issue I have done partial progress. I now longer see
a IOMMU pagefault, but the video plane is heavily corrupted. Also the
dimensions look wrong.

While I can somehow guess that VP_MODE_LINE_SKIP does, the
VP_MODE_FIELD_ID_AUTO_TOGGLING flag still remains a mystery to me. If
possible, I request some documentation for this as well.

With best wishes,

Tobias Jakobi wrote:
> Hello,
> some recent work I did on Exynos. Patches are based on [1] and [2].
> Summary:
> (a) Enables support for NV12MT in the mixer.
> (b) Sanitizes buffer pitch for HW with restrictions.
> (c) Misc fixes
> While testing the NV12MT part, I made these interesting observations.
> (1) I used 1920x1080 XRGB8888 on the primary plane, and 1280x768 on the
> video plane. With this configuration, it does not matter if you're
> using NV12 or NV12MT, the video plane occasionally flickers or shows
> heavy artifacting. Reducing the size of the primary plane, e.g. to
> 32x32 solves this issue, so my guess is that this is memory bandwidth
> issue. Does someone know if one can check for buffer underflows of the
> mixer with respect to data passed from the VP?
> (2) Using 1920x1080i (so an interlaced mode) and NV12, the board
> immediately dies with an IOMMU pagefault at address zero. I'm
> currently investigating this, and it looks like that the VP setup
> is wrong here. In particular it should be the source (!) height
> and vertical position that should be halfed in interlaced mode, and
> not the destination. Need to look more into this.
> Anyway, both the issues are independant of the patches, so please
> review! :-)
> With best wishes,
> Tobias
> [1] http://www.spinics.net/lists/linux-samsung-soc/msg58640.html
> [2] http://www.spinics.net/lists/linux-samsung-soc/msg58644.html
> Tobias Jakobi (8):
>   drm/exynos: mixer: fix chroma comment in vp_video_buffer()
>   drm/exynos: mixer: enable NV12MT support for the video plane
>   drm/exynos: mixer: simplify {vp_video,mixer_graph}_buffer()
>   drm/exynos: mixer: remove src offset from mixer_graph_buffer()
>   drm/exynos: introduce BYTE_PITCH capability
>   drm/exynos: add BYTE_PITCH cap for all supported planes
>   drm/exynos: consistent use of cpp
>   drm/exynos: simplify set_pixfmt() in DECON and FIMD drivers
>  drivers/gpu/drm/exynos/exynos5433_drm_decon.c | 17 +++++------
>  drivers/gpu/drm/exynos/exynos7_drm_decon.c    | 13 +++-----
>  drivers/gpu/drm/exynos/exynos_drm_drv.h       |  2 ++
>  drivers/gpu/drm/exynos/exynos_drm_fb.c        |  2 ++
>  drivers/gpu/drm/exynos/exynos_drm_fimd.c      | 17 ++++-------
>  drivers/gpu/drm/exynos/exynos_drm_plane.c     | 37 ++++++++++++++++++++++
>  drivers/gpu/drm/exynos/exynos_mixer.c         | 44 ++++++++-------------------
>  7 files changed, 71 insertions(+), 61 deletions(-)

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