linux-kernel - Re: [PATCH v6 15/26] drm/bridge: devm_drm_of_get_bridge and drmm_of_get

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Message-ID: <20250207114401.7869b422@booty>
Date: Fri, 7 Feb 2025 11:44:01 +0100
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Simona Vetter <simona@...ll.ch>, Inki Dae <inki.dae@...sung.com>, Jagan
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Subject: Re: [PATCH v6 15/26] drm/bridge: devm_drm_of_get_bridge and
 drmm_of_get_bridge: automatically put the bridge

On Fri, 7 Feb 2025 05:17:43 +0200
Dmitry Baryshkov <dmitry.baryshkov@...aro.org> wrote:

> On Thu, Feb 06, 2025 at 07:14:30PM +0100, Luca Ceresoli wrote:
> > Add a devm/drmm action to these functions so the bridge reference is
> > dropped automatically when the caller is removed.  
> 
> I think the get() should go to the underlying of_drm_bridge_find() function.

It is done in the following patch.

Indeed I could swap patches 15 and 16 for clarity. Or I could squash
together patches 14+15+16, as they are various parts or the refcounted
bridge implementation, but I felt like keeping them separated would
help reviewing.

> Also it really feels like it's an overkill to keep the wrappers. After
> getting bridge being handled by the panel code would it be possible to
> drop all of them?

Do you mean having only drm_of_get_bridge_by_node(), without any devm
or drmm variant? I'm not sure it is a good idea. Most DRM code (well,
all of it, technically) is currently unable of working with refcounted
bridges, but if they use the devm variant they will put the ref when
they disappear.

> Then this patch might introduce one new devm_
> function? Or are drmm_ functions actually being used to store data in
> the drmm-managed memory?

Which devm function are you thinking about? Sorry, I'm not following
here.

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com