[mythtv-users] Video and sound turning off for 2 seconds then returning

[Stephen Worthington]

On Sun, 25 Jul 2021 11:04:36 -0400, you wrote:

>On Sun, Jul 25, 2021 at 10:24 AM Stephen Worthington <
>stephen_agent at jsw.gen.nz> wrote:
>
>> On Sun, 25 Jul 2021 09:17:35 -0400, you wrote:
>>
>> >
>> >On 7/25/21 8:18 AM, Stephen Worthington wrote:
>> >> On Sun, 25 Jul 2021 07:27:16 -0400, you wrote:
>> >>
>> >>> This problem is most likely caused by changing HDMI inputs away from my
>> >>> PC and then back again. It's more subtle than it was a few years ago
>> >>> when I was chasing this on 1080P.
>> >>>
>> >>> I've recently tried setting my PC to UHD 4K with a scale factor of 200%
>> >>> on any *buntu version with 5.11 kernel so I have gfx software new
>> enough
>> >>> to support my 11th gen Intel based NUC.
>> >>>
>> >>> This seems to help 1080 content like mythtv since the TV in UHD
>> improved
>> >>> HD content.
>> >>>
>> >>> If I set my HDMI 2.0 switch to the NUC and boot it, my TV is rock solid
>> >>> regardless of what video I play, mythtv, streaming, games, etc.
>> >>>
>> >>> If I leave the NUC on and switch to another HDMI source and later back
>> >>> to the NUC I get the occasional screen blanking and loss of audio for
>> >>> about 1-2 seconds. This repeats randomly.
>> >>>
>> >>> I can fix this by:
>> >>>
>> >>> 1. rebooting or
>> >>>
>> >>> 2. setting the screen to 1080p 100% scaling.
>> >>>
>> >>> This sound like that old problem where you had to capture the EDID in a
>> >>> file and play with xorg.conf so the settings got reset with an HDMI
>> >>> event like switching.
>> >>>
>> >>> I can't find that old discussion.  I have not had to do any such tricks
>> >>> is a very long time.  This just started when I changed to 4K settings
>> >>> instead of HD.  It's always been a 4K TV. I thought it might be
>> hardware
>> >>> but all the cables and switches are 4K at 60 HDMI 2.0 rated.
>> >>>
>> >>> At this point I just reboot each time I want to connect the PC to to
>> the TV.
>> >>>
>> >>> Any ideas??
>> >> You could get a better HDMI switch - I think there are ones that will
>> >> remember the EDID data and emulate the presence of the TV on any ports
>> >> where the real TV is not connected.  Full KVM switches seem to usually
>> >> have that feature.  But good HDMI KVM switches are not cheap.
>> >
>> >The switch I picked was about $40 and worked great until I started
>> >testing at 4K at 60. I tried using the second HDMI on the TV but had issues
>> >with that, so I didn't spend a lot of time with it. Since I split the
>> >output of the switch with a HDMI 2.0 digital audio extractor. I didn't
>> >want to go that route.
>> >
>> >the switch I use is
>> >
>> >
>> https://www.amazon.com/gp/product/B07MCS9PJD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
>> >
>> >Jim A
>>
>> There is no sign on that page of EDID support, so it likely does not
>> have it.  HDMI switches with EDID support normally tell you as it is
>> an important feature, and justifies higher cost.
>>
>> I did an experiment. I plugged in my NUC PC directly to my HDMI2 TV port.
>I could not see anything until I changed the HDMI UHD color setting to turn
>OFF HDMI 2.0. At that point I could see the PC desktop, but it was only
>4K at 30.  To get 4K at 60 I have to turn on HDMI 2.0 support.
>
>So now I'm back on my HDMI 2.0 Switch and HDMI 2.0 support is turned on for
>that HDMI1 port. The PC is set to 4K at 60 and the TV info shows 4K at 60. I also
>have a Nividia Shield TV connected to the switch and it works at full 4K at 60.
>
>While trying to write this email the screen has blanked out for a second
>twice.
>
>Rebooting seems to be my only choice.  However, I'm very curious why the PC
>directly connected to the TV HDMI2 port can run 4K at 60 with the TV in HDMI
>2.0 mode??
>
>Since the EDID switches are expensive and so are newer UHD TV's, I'm stuff
>for now.
>
>Jim A

If it is an EDID problem, you can always just copy the EDID data and
tell set up the xorg.conf to point to it.  In Ubuntu, install the
read-edid package and run:

get-edid >edid.bin

Put the edid.bin file into /etc/X11, then make the Device section of
/etx/X11/xorg.conf look something like this:

Section "Device"
  Identifier     "nvidia"
  Driver         "nvidia"
  Option         "ConnectedMonitor" "DFP-0"
  Option         "CustomEDID" "DFP-0:/etc/X11/edid.bin"
  Option         "IgnoreEDID" "false"
  Option         "UseEDID" "true"
EndSection

Change the DFP-0 to match what you see in /var/log/Xorg.0.log, and use
the matching Identifier and Driver names.