Re: [PATCH v4 14/23] drm/tilcdc: Provide ddc symlink in connector sysfs directory

[Sam Ravnborg <sam@ravnborg.org>]

Hi Andrej.

On Tue, Jul 23, 2019 at 02:44:50PM +0200, Andrzej Pietrasiewicz wrote:
> Hi Sam,
> 
> W dniu 23.07.2019 o 11:05, Sam Ravnborg pisze:
> > Hi Andrzej
> > 
> > On Thu, Jul 11, 2019 at 01:26:41PM +0200, Andrzej Pietrasiewicz wrote:
> > > Use the ddc pointer provided by the generic connector.
> > > 
> > > Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> > > ---
> > >   drivers/gpu/drm/tilcdc/tilcdc_tfp410.c | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
> > > index 62d014c20988..c373edb95666 100644
> > > --- a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
> > > +++ b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
> > > @@ -219,6 +219,7 @@ static struct drm_connector *tfp410_connector_create(struct drm_device *dev,
> > >   	tfp410_connector->mod = mod;
> > >   	connector = &tfp410_connector->base;
> > > +	connector->ddc = mod->i2c;
> > >   	drm_connector_init(dev, connector, &tfp410_connector_funcs,
> > >   			DRM_MODE_CONNECTOR_DVID);
> > 
> > When reading this code, it looks strange that we set connector->ddc
> > *before* the call to init the connector.
> > One could risk that drm_connector_init() used memset(..) to clear all
> > fields or so, and it would break this order.
> 
> I verified the code of drm_connector_init() and cannot find any memset()
> invocations there. What is your actual concern?
My concern is that drm_connector_init() maybe sometime in the future
will init all fileds in drm_connector, so we loose any assingments
done to drm_connector from *before* we called the init function.

Moving the assignment to after drm_connector_init() would not
let us depend on the actual implmentation of drm_connector_init().

	Sam