2022-04-22 17:46:51

by Jagan Teki

[permalink] [raw]
Subject: Re: [PATCH 2/2] Revert "drm: of: Lookup if child node has panel or bridge"

+ Linus
+ Marek
+ Laurent
+ Robert

On Thu, Apr 21, 2022 at 4:40 AM Bjorn Andersson
<[email protected]> wrote:
>
> Commit '80253168dbfd ("drm: of: Lookup if child node has panel or
> bridge")' attempted to simplify the case of expressing a simple panel
> under a DSI controller, by assuming that the first non-graph child node
> was a panel or bridge.
>
> Unfortunately for non-trivial cases the first child node might not be a
> panel or bridge. Examples of this can be a aux-bus in the case of
> DisplayPort, or an opp-table represented before the panel node.
>
> In these cases the reverted commit prevents the caller from ever finding
> a reference to the panel.
>
> This reverts commit '80253168dbfd ("drm: of: Lookup if child node has
> panel or bridge")', in favor of using an explicit graph reference to the
> panel in the trivial case as well.

This eventually breaks many child-based devm_drm_of_get_bridge
switched drivers. Do you have any suggestions on how to proceed to
succeed in those use cases as well?

Jagan.