Re: [Intel-gfx] [PATCH 01/15] drm/i915/hdmi: do dual mode detect only if connected

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

On Thu, Oct 20, 2022 at 11:57:06AM +0300, Jani Nikula wrote:
> On Wed, 19 Oct 2022, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> > On Thu, Oct 13, 2022 at 10:24:54PM +0300, Ville Syrjälä wrote:
> >> On Thu, Oct 13, 2022 at 09:41:21PM +0300, Ville Syrjälä wrote:
> >> > On Tue, Oct 11, 2022 at 04:49:35PM +0300, Jani Nikula wrote:
> >> > > -	intel_hdmi_dp_dual_mode_detect(connector, edid != NULL);
> >> > > -
> >> > > -	intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS, wakeref);
> >> > > -
> >> > >  	to_intel_connector(connector)->detect_edid = edid;
> >> > >  	if (edid && edid->input & DRM_EDID_INPUT_DIGITAL) {
> >> > 
> >> > We didn't have this digital input thing before. What happens with
> >> > HDMI->VGA dongles for example?
> >> > 
> >> > Hmm. This whole thing might already be broken on those. I suspect
> >> > I've only used my HDMI->VGA dongle on LSPCON machines, so never
> >> > noticed this. Need to go plug that thing into a native HDMI port...
> >> 
> >> Except I must have left it elsewhere since I can't find it here.
> >> So can't test right now unfortunately.
> >> 
> >> I first thought this digital check thing might be due to
> >> the DVI-I shenanigans in intel_crt_detect_ddc(), but that
> >> was added for am unspecified gen2 machine in commit f5afcd3dd0dc
> >> ("drm/i915/crt: Check for a analog monitor in case of DVI-I")
> >> so not even relevant here. And I don't think I've ever seen
> >> a g4x+ machine with an actual DVI-I port.
> >
> > Good news everyone, I found such a board: Intel DG43GT.
> > Well, I didn't physically find one but I found the manual
> > online. And some coreboot repo even had the vbt handily
> > available. And yes, it does show the same DDC pins being
> > used for the DVI-D port and CRT port. So I guess given
> > that these digital checks do make some sense.
> 
> So what's the conclusion wrt the patch at hand?

Seems fine as is for the moment. We'll know more once I locate
my dongle again.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

-- 
Ville Syrjälä
Intel