linux-kernel - Re: [PATCH] drm/vkms: Remove useless call to drm_connector_register()

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Date:   Mon, 11 Mar 2019 19:50:07 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>
Cc:     David Airlie <airlied@...ux.ie>,
        Haneen Mohammed <hamohammed.sa@...il.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/vkms: Remove useless call to drm_connector_register()

On Mon, Mar 11, 2019 at 03:00:04PM -0300, Rodrigo Siqueira wrote:
> On 03/11, Daniel Vetter wrote:
> > On Sun, Mar 10, 2019 at 06:22:41PM -0300, Rodrigo Siqueira wrote:
> > > The function vkms_output_init() is invoked during the module
> > > initialization, and it handles the creation/configuration of the vkms
> > > essential elements (e.g., connectors, encoder, etc). Among the
> > > initializations, this function tries to initialize a connector and
> > > register it by calling drm_connector_register(). However, inside the
> > > drm_connector_register(), at the beginning of this function there is the
> > > following validation:
> > > 
> > >  if (!connector->dev->registered)
> > >    return 0;
> > > 
> > > In this sense, invoke drm_connector_register() after initializing the
> > > connector has no effect because the register field is false. The
> > > connector register happens when drm_dev_register() is invoked.
> > > Therefore, this commit removes the drm_connector_register() from
> > > vkms_output_init().
> > > 
> > > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>
> > > ---
> > >  drivers/gpu/drm/vkms/vkms_output.c | 6 ------
> > >  1 file changed, 6 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
> > > index 3b162b25312e..a6cee4c279c2 100644
> > > --- a/drivers/gpu/drm/vkms/vkms_output.c
> > > +++ b/drivers/gpu/drm/vkms/vkms_output.c
> > > @@ -71,12 +71,6 @@ int vkms_output_init(struct vkms_device *vkmsdev)
> > >  
> > >  	drm_connector_helper_add(connector, &vkms_conn_helper_funcs);
> > >  
> > > -	ret = drm_connector_register(connector);
> > 
> > Yeah that's only needed for connectors added when hotplugging at runtime,
> > not for connectors which are created at driver load time.
> > 
> > Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>
> > 
> > btw same issue exists with the drm_connector_unregister, that's also not
> > needed.
> 
> Thanks for your review :)
> 
> Should I send a V2 that also removes the drm_connector_unregister()? Or
> should I send it in a separated patch?

Either is fine with me. Either has my r-b.
-Daniel

> 
> Best Regards
> 
> > -Daniel
> > 
> > > -	if (ret) {
> > > -		DRM_ERROR("Failed to register connector\n");
> > > -		goto err_connector_register;
> > > -	}
> > > -
> > >  	ret = drm_encoder_init(dev, encoder, &vkms_encoder_funcs,
> > >  			       DRM_MODE_ENCODER_VIRTUAL, NULL);
> > >  	if (ret) {
> > > -- 
> > > 2.21.0
> > 
> > -- 
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
> 
> -- 
> Rodrigo Siqueira
> https://siqueira.tech
> Graduate Student
> Department of Computer Science
> University of São Paulo


> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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