Re: CVS commit: src/sys/arch/arm/allwinner

[Jared McNeill <jmcneill%invisible.ca@localhost>]

I don't mind turning off TCON, but I think we need to take HDMI audio into 
consideration when doing so. I don't think interrupting audio output is a 
good idea. Unfortunately wscons only give us an on/off switch so we need 
to be smart about it in the kernel. So I think the blanking solution needs 
to take the following into consideration:

 - Active HDMI audio when blanking the screen should not disable TCON.
 - When HDMI audio finishes and the screen is in "blanked" state, then
   disable TCON.
 - A disabled TCON should be re-enabled when starting HDMI audio.



On Mon, 5 Oct 2015, Manuel Bouyer wrote:

> On Mon, Oct 05, 2015 at 12:20:57PM -0300, Jared McNeill wrote:
> > Not sure I like this. Disabling TCON interferes with HDMI audio (and this is
> > why the code was the way that it was) and I'm not aware of any "blank screen
> > but keep audio active" mechanism for HDMI displays.
>
> So you say we should also disable HDMI audio ?
> Maybe we could add a callback in awin_hdmi.c to turn on/off HDMI completely ?
>
> BTW, I'm looking at this because I need to make the LVDS interface to work
> (and turn the display on/off via GPIOs, to save power). Do you have ideas
> on how this should work ?
> We won't have EDID source in this case; for the omap controller I did
> hardcode a video mode in sources, which is quite ugly.
>
> --
> Manuel Bouyer <bouyer%antioche.eu.org@localhost>
>     NetBSD: 26 ans d'experience feront toujours la difference
> --