Re: [PATCH] drm/scdc-helper: Pimp SCDC debugs

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Mar 30, 2023 at 10:44:04AM +0200, Maxime Ripard wrote:
> Hi,
> 
> On Wed, Mar 29, 2023 at 08:14:02PM +0300, Ville Syrjala wrote:
> > diff --git a/drivers/gpu/drm/display/drm_scdc_helper.c b/drivers/gpu/drm/display/drm_scdc_helper.c
> > index c3ad4ab2b456..2b124152384c 100644
> > --- a/drivers/gpu/drm/display/drm_scdc_helper.c
> > +++ b/drivers/gpu/drm/display/drm_scdc_helper.c
> > @@ -26,6 +26,8 @@
> >  #include <linux/delay.h>
> >  
> >  #include <drm/display/drm_scdc_helper.h>
> > +#include <drm/drm_connector.h>
> > +#include <drm/drm_device.h>
> >  #include <drm/drm_print.h>
> >  
> >  /**
> > @@ -140,6 +142,7 @@ EXPORT_SYMBOL(drm_scdc_write);
> >  
> >  /**
> >   * drm_scdc_get_scrambling_status - what is status of scrambling?
> > + * @connector: connector
> >   * @adapter: I2C adapter for DDC channel
> >   *
> >   * Reads the scrambler status over SCDC, and checks the
> > @@ -148,14 +151,17 @@ EXPORT_SYMBOL(drm_scdc_write);
> >   * Returns:
> >   * True if the scrambling is enabled, false otherwise.
> >   */
> > -bool drm_scdc_get_scrambling_status(struct i2c_adapter *adapter)
> > +bool drm_scdc_get_scrambling_status(struct drm_connector *connector,
> > +				    struct i2c_adapter *adapter)
> 
> Is there any driver where adapter isn't equal to connector->ddc?

I figured most of them since they all maintain their own ddc
pointer elsewhere. But looks like the drivers using the scdc
helper might all be setting connector->ddc for their HDMI
connectors despite that.

Even i915 does that apparently. My recollection was otherwise
since I have a branch waiting somewhere that changes the whole
driver to use connector->ddc.

I guess someone took a bunch of shortcuts to get connector->ddc
populated but then didn't finish the job by clearing out the
old pointers.

> 
> If not, there's no reason to pass both

Yeah, that did cross my mind. But left it out with in
the belief that it can't be done yet.

-- 
Ville Syrjälä
Intel