[RFC 0/2] drm/bridge: panel and chaining

[Sean Paul]

On Tue, Apr 29, 2014 at 3:57 PM, Rob Clark <robdclark at gmail.com> wrote:
> So I thought it would be easier to explain what I had in mind regarding
> Ajay's patchset (to add panel support) in patch form.  Originally Thierry
> had some concerns with adding panel support in bridges ad-hoc.  So this
> idea adds the support of chaining multiple bridges, one of which may be
> a panal adapter (maybe I should have called it drm_panel_adapter_bridge).
> There are a few rough edges and TODOs, it isn't trying to be complete
> yet.
>
> So the one question is about that hunk I had to move in ptn3460 from
> pre_enable() to enable().  If that really needs to come before the
> encoder and after the panel, then we should go for a slightly different
> approach instead: add a 'struct drm_bridge *next' ptr in 'struct
> drm_bridge'.  Then each bridge implementation is responsible to call
> the next in the chain (if not null) at the appropriate points.  That
> gives a bit more flexibility to bridges to have something both pre and
> post the downstream bridge/panel in each of the pre/enable/disable/post
> steps.

Arbitrarily chaining bridges seems like a more robust solution to me
than the composite bridge.

For the panel case, I wonder if we could change drm_bridge_init to
accept a panel, then we could just chain the panel calls off the
various places the bridge hooks are invoked in the drm layer.

Feel free to ignore if this has already been explored on the other
thread (which I haven't been following).

Sean



>
>
> Rob Clark (2):
>   drm/bridge: add composite and panel bridges
>   drm/bridge/ptn3460: add panel support
>
>  drivers/gpu/drm/bridge/Makefile          |   2 +
>  drivers/gpu/drm/bridge/drm_bridge_util.c | 251 +++++++++++++++++++++++++++++++
>  drivers/gpu/drm/bridge/drm_bridge_util.h |  29 ++++
>  drivers/gpu/drm/bridge/ptn3460.c         |  39 ++++-
>  include/drm/bridge/ptn3460.h             |   6 +-
>  5 files changed, 319 insertions(+), 8 deletions(-)
>  create mode 100644 drivers/gpu/drm/bridge/drm_bridge_util.c
>  create mode 100644 drivers/gpu/drm/bridge/drm_bridge_util.h
>
> --
> 1.9.0
>
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