[Letux-kernel] drm/omap: Remove panel-dpi driver

[Tomi Valkeinen]

On 11/04/2019 09:14, H. Nikolaus Schaller wrote:

>> You will need the panel data to be added to the simple panel driver, as
>> it won't read the timings from the DT (unfortunately, in my opinion).
> 
> Hm. How does this work? Is there a description? I have no experience with
> DRM simple panel.

See drivers/gpu/drm/panel/panel-simple.c, it just has a list of
compatibles, and pointers to the (more or less) same data as is in the
DT. And see a commit that adds a new panel, e.g. "drm/panel: simple: Add
OSD070T1718-19TS panel support".

> So with this DTB stability policy in mind it seems too early to remove the
> panel-dpi driver unless there is a compatible solution which does not break
> existing DTB.

Well, maybe just reverting "drm/omap: Remove panel-dpi driver" would be
enough. I didn't try, but I think all the plumbing is still there to
keep the legacy omapdrm panels working.

If I'm not mistaken, Laurent did try to get the simple-panel to get the
timings from the DT, but it was rejected. Perhaps backward-compatibility
with out-of-tree dtbs would be a valid reason to get it accepted?
Laurent, what do you think?

That said, in my opinion, we should not care too much about out-of-tree
stuff. It's a nightmare to support things that you're not even aware of.
In this particular case, adding the out-of-tree panels to simple-panel
should be a very straightforward task, and doesn't need a change in the
dtbs themselves.

 Tomi

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