Re: [PATCH] drm: Don't generate invalid AVI infoframes for CEA modes

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

On Mon, Aug 05, 2013 at 07:18:27PM +0100, Damien Lespiau wrote:
> On Mon, Aug 05, 2013 at 09:07:05PM +0300, Ville Syrjälä wrote:
> > On Mon, Aug 05, 2013 at 02:36:47PM +0100, Damien Lespiau wrote:
> > > >From CEA-861:
> > > 
> > >   Data Byte 1, bit A0 indicates whether Active Format Data is present in
> > >   Data Byte 2 bits R3 through R0. A source device shall set A0=1 when
> > >   any of the AFD bits are set.
> > > 
> > > ie. if we want to set active_aspect, we need to set the
> > > active_info_valid bit to 1 as well.
> > > 
> > > Cc: Thierry Reding <thierry.reding@avionic-design.de>
> > > Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
> > > ---
> > >  drivers/gpu/drm/drm_edid.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > > index 95d6f4b..8d1139f 100644
> > > --- a/drivers/gpu/drm/drm_edid.c
> > > +++ b/drivers/gpu/drm/drm_edid.c
> > > @@ -3107,6 +3107,7 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
> > >  		return 0;
> > 
> > Nothing to do with this patch, but I just spotted this return here. So
> > we're not populating the aspect ratio stuff if VIC=0. Doesn't really
> > make sense to me. Who will tell me what this is trying to achieve?
> 
> I wondered about that to. The intent seems to not set those bits when
> we're not setting a CEA mode. I guess the author thought that only CEA
> modes can understand the infoframes described in CEA-861. I haven't
> found any evidence of that, but made some sense to me.

Perhaps. I'm leaning towards just killing that check though.

-- 
Ville Syrjälä
Intel OTC