[PATCH 09/64] drm/simple: Introduce drmm_simple_encoder_init

[Maxime Ripard]

On Mon, Jun 20, 2022 at 04:25:38PM +0200, Thomas Zimmermann wrote:
> Hi
> 
> Am 20.06.22 um 15:48 schrieb Maxime Ripard:
> > Hi,
> > 
> > On Mon, Jun 20, 2022 at 12:44:24PM +0200, Thomas Zimmermann wrote:
> > > Am 10.06.22 um 11:28 schrieb Maxime Ripard:
> > > > The DRM-managed function to register an encoder is
> > > > drmm_simple_encoder_alloc() and its variants, which will allocate the
> > > > underlying structure and initialisation the encoder.
> > > > 
> > > > However, we might want to separate the structure creation and the encoder
> > > > initialisation, for example if the structure is shared across multiple DRM
> > > > entities, for example an encoder and a connector.
> > > > 
> > > > Let's create an helper to only initialise an encoder that would be passed
> > > > as an argument.
> > > > 
> > > 
> > > There's nothing wrong with this patch, but I have to admit that adding
> > > drm_simple_encoder_init() et al was a mistake.
> > 
> > Why do you think it was a mistake?
> 
> The simple-encoder stuff is an interface that no one really needs. Compared
> to open-coding the function, it's barely an improvement in LOCs, but nothing
> else.
> 
> Back when I added drm_simple_encoder_init(), I wanted to simplify the many
> drivers that initialized the encoder with a cleanup callback and nothing
> else.  IIRC it was an improvement back then.  But now we already have a
> related drmm_ helper and a drmm_alloc_ helper. If I had only added the macro
> back then, we could use the regular encoder helpers.
> 
> > 
> > > It would have been better to add an initializer macro like
> > > 
> > > #define DRM_STATIC_ENCODER_DEFAULT_FUNCS \
> > >    .destroy = drm_encoder_cleanup
> > > 
> > > It's way more flexible and similarly easy to use. Anyway...
> > 
> > We can still have this. It would simplify this series so I could
> > definitely squeeze that patch in and add a TODO item / deprecation
> > notice for simple encoders if you think it's needed
> 
> Not necessary. It's not super important.

The corollary is though :)

If I understand you right, it means that you'd rather have a destroy
callback everywhere instead of calling the _cleanup function through a
drm-managed callback, and let drm_dev_unregister do its job?

If so, it means that we shouldn't be following the drmm_.*_alloc
functions and should drop all the new ones from this series.

Maxime
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