I have a new(ish) desktop system with an ASUS Radeon RX6600.
It had been working fine since overcoming teething troubles.

After I lifted it back onto its shelf slot beneath my desk, one screen
(of two) wouldn't display. It turned out that neither screen/lead would
work if driven from the sole HDMI socket.

The still working screen is plugged into a displayport socket using a
DP-to-HDMI converter. In desperation I have ordered another!

I cannot recall any BIOS settings related to displays nor any way of
finding out why bthe problem occurred.

Why post here?

There was always a chance that someone has encountered the same poblem
and found a solution.

ATB Alan

--
Linux Mint 21.3 kernel version 5.15.0-101-generic Cinnamon 6.0.4
AMD Ryzen 7 7700, Radeon RX 6600, 32GB DDR5, 1TB SSD, 2TB Barracuda

On 4/5/2024 8:01 AM, pinnerite wrote:
> I have a new(ish) desktop system with an ASUS Radeon RX6600.
> It had been working fine since overcoming teething troubles.
>
> After I lifted it back onto its shelf slot beneath my desk, one screen
> (of two) wouldn't display. It turned out that neither screen/lead would
> work if driven from the sole HDMI socket.
>
> The still working screen is plugged into a displayport socket using a
> DP-to-HDMI converter. In desperation I have ordered another!
>
> I cannot recall any BIOS settings related to displays nor any way of
> finding out why bthe problem occurred.
>
> Why post here?
>
> There was always a chance that someone has encountered the same poblem
> and found a solution.
>
> ATB Alan
>

I think I may have told you my story, about buying a
DP to HDMI active adapter, and how handy it turned out
to be for problems of that nature.

So yes, there appears to be some issue with HDMI,
like a compatibility issue. But I don't have any
means of debugging what is going on.

Before despairing, you should test with both your good
screen and your bad screen, in "span" mode, and see if
you can cause it to (eventually) turn on. It could
be the issue that video cards have, with "which connector
is the prime connector". On my Test Machine with the
GTX1080 video card, it likes to drive out on the
wrong connector at startup, but only once every five
boots or so. Yours could randomly work after yet
another reboot. Since I know which connector it "likes"
to drive, I cable up using that, and then it is happy.

Summary: No idea what the real root causes of these behaviors is,
but there are workarounds. Just stock the correct
materials in your "fix stupid problems bag".
The Active DP to HDMI should work for at least
1920x1080 situations. Don't know if 4K ones are available.
Things like HDCP may make it harder to make a full featured
4K adapter of that type.

Paul

On Fri, 5 Apr 2024 14:08:51 -0400
Paul <nospam@needed.invalid> wrote:

> On 4/5/2024 8:01 AM, pinnerite wrote:
> > I have a new(ish) desktop system with an ASUS Radeon RX6600.
> > It had been working fine since overcoming teething troubles.
> >
> > After I lifted it back onto its shelf slot beneath my desk, one screen
> > (of two) wouldn't display. It turned out that neither screen/lead would
> > work if driven from the sole HDMI socket.
> >
> > The still working screen is plugged into a displayport socket using a
> > DP-to-HDMI converter. In desperation I have ordered another!
> >
> > I cannot recall any BIOS settings related to displays nor any way of
> > finding out why bthe problem occurred.
> >
> > Why post here?
> >
> > There was always a chance that someone has encountered the same poblem
> > and found a solution.
> >
> > ATB Alan
> >
>
> I think I may have told you my story, about buying a
> DP to HDMI active adapter, and how handy it turned out
> to be for problems of that nature.
>
> So yes, there appears to be some issue with HDMI,
> like a compatibility issue. But I don't have any
> means of debugging what is going on.
>
> Before despairing, you should test with both your good
> screen and your bad screen, in "span" mode, and see if
> you can cause it to (eventually) turn on. It could
> be the issue that video cards have, with "which connector
> is the prime connector". On my Test Machine with the
> GTX1080 video card, it likes to drive out on the
> wrong connector at startup, but only once every five
> boots or so. Yours could randomly work after yet
> another reboot. Since I know which connector it "likes"
> to drive, I cable up using that, and then it is happy.
>
> Summary: No idea what the real root causes of these behaviors is,
> but there are workarounds. Just stock the correct
> materials in your "fix stupid problems bag".
> The Active DP to HDMI should work for at least
> 1920x1080 situations. Don't know if 4K ones are available.
> Things like HDCP may make it harder to make a full featured
> 4K adapter of that type.
>
> Paul
>

It turned out to be the socket on the monitor.
It plug could (too) easily be disturbed to an iffy connection.

Alan

--
Linux Mint 21.3 kernel version 5.15.0-101-generic Cinnamon 6.0.4
AMD Ryzen 7 7700, Radeon RX 6600, 32GB DDR5, 1TB SSD, 2TB Barracuda