Re: [PATCH 16/18] drm/i915/sdvo: Read out HDMI infoframes

Ville Syrjälä
2018-10-01T13:35:50Z

On Mon, Oct 01, 2018 at 08:59:41AM +0200, Daniel Vetter wrote:
> On Mon, Sep 24, 2018 at 08:13:08PM +0300, Ville Syrjälä wrote:
> > On Mon, Sep 24, 2018 at 06:10:14PM +0200, Daniel Vetter wrote:
> > > On Thu, Sep 20, 2018 at 09:51:43PM +0300, Ville Syrjala wrote:
> > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > >
> > > > Read the HDMI infoframes from the hbuf and unpack them into
> > > > the crtc state.
> > > >
> > > > Well, actually just AVI infoframe for now but let's write the
> > > > infoframe readout code in a more generic fashion in case we
> > > > expand this later.
> > > >
> > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > >
> > > Hm, caring about sdvo seems a bit overkill. And afaik we don't have any
> > > sdvo (much less hdmi) in CI. I'm leaning towards just adding a
> > > PIPE_CONFIG_QUIRK_INFOFRAMES for sdvo, and short-circuiting the checks if
> > > that's set. Except if you can somehow convince CI folks to add an sdvo
> > > hdmi card to CI :-)
> >
> > Unfortunately I only have one SDVO HDMI device and it has the chip
> > straight on the motherboard. I can't give mine up for ci :) I guess
> > we could try to find another one of those as that model doesn't
> > even seem super rare. Just the annoying usual problem of getting
> > one from somewhere approved.
> >
> > I think having to maintain a quirk is ~500% more annoying than
> > adding the readout code.
>
> My experience disagrees, a bunch of the (early?) sdvo chips don't bother
> to implement all the get stuff. I had a pile of these (but some of them
> died, and plugging them all into machines is a pain), and just because it
> works on 1 chip doesn't mean it's actually all that useful. That's why I
> suggested we do the same thing as with the other stuff we read out from
> the sdvo chip (as opposed to things we can read out from
> crtc/sdvo-host-side registers).

We do read out the hdmi encoding and pixel multipler from
the sdvo chip already. If the chips don't implement the hdmi
stuff we treat them as dvi. I have some (supposedly) hdmi
add2 cards like that. So I don't think those pose any kind
of real problem.

--
Ville Syrjälä
Intel