[PATCH] drm/edid: request HDMI underscan by default

Damien Lespiau damien.lespiau at intel.com
Thu Feb 27 07:49:10 PST 2014


On Thu, Feb 27, 2014 at 05:42:36PM +0200, Ville Syrjälä wrote:
> On Thu, Feb 27, 2014 at 09:19:30AM -0600, Daniel Drake wrote:
> > Working with HDMI TVs is a real pain as they tend to overscan by
> > default, meaning that the pixels around the edge of the framebuffer
> > are not displayed. This is well explained here:
> > http://mjg59.dreamwidth.org/8705.html
> > 
> > There is a bit in the HDMI info frame that can request that the
> > remote display shows the full pixel data ("underscan"). For the
> > remote display, the HDMI spec states that this is optional - it
> > doesn't have to listen. That means that most TVs will probably ignore
> > this.
> > 
> > But, maybe there are a handful of TVs for which this would help
> > the situation. As we live in a digital world, ask the remote
> > display not to overscan by default.
> > 
> > Signed-off-by: Daniel Drake <drake at endlessm.com>
> 
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

As a small note, I never managed to find a TV (out of the 2 I have
around) that honour that flag, which is why I haven't pushed that patch
before. I also had the hope that we could automatically overscan with
the right amount at some point (with some sort of database) and with
that flag set, we don't know if the sink is overscanning or not, but
then I guess we could include whether the TV honour in that flag in a db
as well.

In any case, I echo the review:

Reviewed-by: Damien Lespiau <damien.lespiau at intel.com>

-- 
Damien


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