[PATCH v2 0/3] drm: introduce bus_flags for pixel clock polarity

Stefan Agner stefan at agner.ch
Tue Feb 23 23:30:03 UTC 2016

Any comments on this?

Also added Manfred, Tomi and Boris to CC which previously attended in
similar discussions.

Previous discussions:

I think one of the main observation so far was that the pixel clock
polarity is not a property of the mode, and therefor does not fit into
the DRM_MODE_FLAG. This has been pointed out nicely by Russel:

Embedded displays connected through parallel bus make use of the
bus_formats field in drm_display_mode. This field defines what kind of
bus format the display requires. This patch follows that idea and adds
bus_flags. bus_flags can be used to define specific bus properties
required by the display, such as pixel clock or data enable polarity...

On 2016-02-08 13:57, Stefan Agner wrote:
> Hi,
> This is a new & split out version of the last patch of my
> "drm/fsl-dcu: fixes and enhancements" patchset:
> https://lkml.org/lkml/2015/11/18/949
> Instead of using struct drm_display_mode to convey the pixel clock
> polarity information, this patchset introduces a new field called
> bus_flags stored in struct drm_display_info.

Note that this solution has been briefly discussed on IRC:


> Changes since v1:
> - Introduce bus_flags to convey the pixel clock polarity from
>   panel-simple.c to the driver.
> Stefan Agner (3):
>   drm/fsl-dcu: use mode flags for hsync/vsync polarity
>   drm: introduce bus_flags in drm_display_info
>   drm/fsl-dcu: use bus_flags for pixel clock polarity
>  drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c | 16 +++++++++++++---
>  drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h  |  4 ++--
>  drivers/gpu/drm/panel/panel-simple.c       |  6 +++++-
>  include/drm/drm_crtc.h                     |  9 +++++++++
>  4 files changed, 29 insertions(+), 6 deletions(-)

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