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

David Hampton mythtv at love2code.net
Mon Jul 26 03:29:03 UTC 2021


On Mon, 2021-07-26 at 14:39 +1200, Stephen Worthington wrote:
> 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.

You don't need an full xorg.conf file any longer. You can put just the
non-default bits you need in individual files in the xorg.conf.d
directory, although I believe the files have to start with a two digit
number and end with ".conf', i.e. 50-xorg-tweaks-intel.conf. Your call
on whether to use one file or multiple. On my system with an Intel
HD500 I have 'Option "HotPlug" "false"' in the Monitor section. This
might help the screen blanking with your Intel Xe Graphics. That sounds
like it could be monitor auto-detection kicking in. What does your log
file say when the blanking happens?

The other way to set the EDID is from the kernel command line. You can
add "drm.edid_firmware=<yourEdidFilename>" to the kernel arguments in
grub. The file name is relative to the /lib/firmware directory. I have
my system set up this way, although I can't remember what forced me to
this from the xorg.conf.d method that I had been using for years. (I
can't tell from the earlier discussion whether you have multiple
displays, and I don't know what this assignment would do with multiple
displays. I assume it would assign them all the same edid file.)

David




More information about the mythtv-users mailing list