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

[Stephen Worthington]

On Sun, 25 Jul 2021 14:16:51 -0400, you wrote:

>On Sun, Jul 25, 2021 at 12:38 PM Stephen Worthington <
>stephen_agent at jsw.gen.nz> wrote:
>
>> 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.
>>
>
>So currently I don't have an xorg.conf.  So how is the correct way to
>create it so I can change the Device section?
>
>Also my system only has the Intel Xe Graphics.
>
>FYI my Xorg.log is at: "/home/jim/.local/share/xorg/Xorg.1.log"
>
>Checking there I think the DFP-0 should be HDMI-1
>
>[    30.185] (II) modeset(0): EDID for output DP-1
>[    30.227] (II) modeset(0): EDID for output HDMI-2
>[    30.227] (II) modeset(0): EDID for output DP-2
>[    30.227] (II) modeset(0): EDID for output DP-3
>[    30.227] (II) modeset(0): Output HDMI-1 connected
>[    30.227] (II) modeset(0): Output DP-1 disconnected
>[    30.227] (II) modeset(0): Output HDMI-2 disconnected
>[    30.227] (II) modeset(0): Output DP-2 disconnected
>[    30.227] (II) modeset(0): Output DP-3 disconnected
>
>Jim A

You will need to create a bare-bones xorg.conf manually.  There are
automated ways of doing it (eg "X -configure" from a TTY with the
desktop shut down), but they will create far too much configuration
with detailed settings for everything.  What you want is just to
specify the minimum, add your EDID bits, and leave the rest to be set
up automatically by X.  A template for what you need is here:

https://wiki.ubuntu.com/X/Config

You will need to look at the relevant Xorg.*.log file to find the
names being used for everything.  As well as referencing the hardware
devices, they are used to match the sections of config together, so
the "Monitor" name in the "Screen" section needs to reference the
"Identifier" name you used in the "Monitor" section.  There are heaps
of examples of xorg.conf files posted on the net to look at, but do
not be tempted to just copy one as that never works due to the names
not matching.

BTW I am surprised that your Xorg.1.log file is using 1 for the
display number.  That normally only happens if you are running more
than one display - the first display is usually numbered 0.  So it
might pay to see if you do have an Xorg.0.log file somewhere.  If you
have the mlocate package installed, run "updatedb" and then "locate
Xorg.0.log".  And check the timestamp on the log file to make sure it
is the one that X is currently writing to.