[Intel-gfx] [PATCH 1/4] drm/i915: Configure the TV sense state correctly on GM45 to make TV detection reliable

[ykzhao]

On Wed, 2010-04-07 at 22:17 +0800, Adam Jackson wrote:
> On Wed, 2010-04-07 at 17:11 +0800, Zhenyu Wang wrote:
> > From: ykzhao <yakui.zhao at intel.com>
> > 
> > The TV detection logic is not reliable on the Cantiga platform.
> > Sometimes the TV will be misdetected as the following two cases:
> > - TV is misdetected on some laptops. e.g. There is no TV connector
> > port or no TV is attached. But the TV is shown as connected.
> > - TV connector type is misdetected. e.g. the component TV is
> > attached, but the TV is shown as S-video type.
> > 
> > According to the hardware requirement, the TV sense state bits of TV DAC
> > register should be cleared to zero on Cantiga platfrom.
> 
> Is it worth doing this for all platforms?  Seems like it can't hurt.


I also do some test on three machines with integrated TV by using low
level for TV sense control. It is very surprising that the TV also can
be detected correctly.
    >The three machines are based on 915GM/945GM/965GM.

In fact I only do the tests on three machines. I am not sure whether it
can work well on some other machines as expected.

At the same time according to the spec the sense state should be set to
high. And it seems that the current detection logic can work well on the
915GM/945GM/965GM.  Maybe we can still use the high level sense control
for the other platform. 

Anyway, it is still a good point that the sense state bits are clearedto
zero on the other platforms.

Thanks.
   Yakui

> 
> - ajax