[Yabbie442]

Hello,

I run Kodi on my Pi4 and when I switch to HDMI, I get often get 'No signal' on my TV. Rebooting my Kodi service results in everything working again.

If I switch from HDMI to (say Netfix) and then come back to HDMI later, once again I get "No signal".

I never had this issue on Buster, its only been since I switched to Bullseye. So I don't believe there is any kind of hardware issue. It must be a config issue, or a bug.

Setup:

LG C9 OLED TV.
Pi 4

Linux raspberrypi 5.15.32-v8+ #1538 SMP PREEMPT Thu Mar 31 19:40:39 BST 2022 aarch64

/boot/config.txt:
# Enable DRM VC4 V3D driver
dtoverlay=vc4-kms-v3d,cma-512
max_framebuffers=2

# Hardware HEVC acceleration
dtoverlay=rpivid-v4l2

Tried my best to search for an answer (I'm a beginner) and the best I could come up with was that it might be some sort of KMS vs FKMS thing.

As always, appreciate any help.

[popcornmix]

It's not quite clear which order you are doing things in, but the Pi needs to be able to read the edid of display when it boots.

What this means varies by TV.
For most, just plugged in by hdmi is enough.
For others they need to be powered on (i.e. not in standby)
and for others they need to also have the correct AV input selected.

If you are hitting this, then you can capture the edid to a file, so it's always available (but note, you'll need to repeat this if you change to a different TV).

Code:

sudo cp /sys/devices/platform/gpu/drm/card?/card?-HDMI-A-1/edid /lib/firmware/edid.dat

and add to the end of /boot/cmdline.txt (on same line)

Code:

drm.edid_firmware=HDMI-A-1:edid.dat video=HDMI-A-1:D

[Yabbie442]

It's not quite clear which order you are doing things in, but the Pi needs to be able to read the edid of display when it boots.

Firstly, I want to point out that how I'm doing things now, is how I've always done them, and that was never an issue while using Buster.  Point being, if the EDID was working then, it should be working now.

Typically, the Pi is running.  As is Kodi.  Then I turn on the TV and change the input to HDMI. 

This is when I sometimes get "No signal".  However, not always.  Sometimes, Kodi is there to greet me, as I would expect.

Restarting the Kodi service fixes the issue each time, but you said above the Pi needs to be able to read the EDID of the display when it boots.  I'm not rebooting the Pi, just restarting the Kodi service (unless you meant Kodi when you said Pi?).

Also, CEC was working (under the current setup), but when I have this issue, it stops working and I have to control Kodi with the app on my phone.  Not sure if this gives any extra information?

[Yabbie442]

Thank you for the reply popcornmix, I hope this doesn't sound rude at all (because it's not meant to in the slightest), but I'd love to get to the bottom of this issue, rather than find a 'workaround', which is what I consider your edid.dat solution.

[Yabbie442]

So there are actually two separate, but (possibly) related problems.

1.  Sometimes, when I turn on my TV and switch to HDMI source (or power on the TV with the HDMI set as the source already), I get "No Signal" (which is 'fixed' by restarting Kodi (but not the Pi itself)).

2.  CEC only works sometimes.

Notes:
3.  I always keep my Pi up to date (run apt update almost daily).
4.  I haven't (knowingly) changed my TV configuration.
5.  The TV firmware has updated itself a few times, but again, this was never an issue under Buster.
6.  All of this worked fine under Buster.  Not complaining, just saying.

[Klojum]

CEC itself is a grab bag of options. Each TV manufacturer has its own implementation of CEC, hell they each have their own name for the same technology. So, it often is a situation of "try and find out if it works".

[popcornmix]

Thank you for the reply popcornmix, I hope this doesn't sound rude at all (because it's not meant to in the slightest), but I'd love to get to the bottom of this issue, rather than find a 'workaround', which is what I consider your edid.dat solution.

Finding exactly what causes the "no signal" would be useful.
e.g. does switching AV input away from kodi to another source and back make it occur?
does powering TV off and on make it occur?

ssh in to pi before testing this. After "no signal" is ssh connection still working? Does dmesg show any new messages?

[Yabbie442]

 

Finding exactly what causes the "no signal" would be useful.
e.g. does switching AV input away from kodi to another source and back make it occur?
does powering TV off and on make it occur?

ssh in to pi before testing this. After "no signal" is ssh connection still working? Does dmesg show any new messages?

does switching AV input away from kodi to another source and back make it occur? - No, it seems to need to be 'away' from that source for a while.  And even then, it only happens sometimes.

does powering TV off and on make it occur? - No.

ssh in to pi before testing this. After "no signal" is ssh connection still working? - Yes, always.

Does dmesg show any new messages?  Now this is more interesting.  I've never heard of dmesg before (told you I'm new, lol).

dmesg output:  [608454.365301] cec-vc4: message 10 timed out

And a *whole* lot more messages identical, just with different numbers in the square brackets (timestamp?)

[Yabbie442]

base64 /sys/devices/platform/gpu/drm/card1/card1-HDMI-A-1/edid

AP///////wAebaDAAQEBAQEdAQOAoFp4Cu6Ro1RMmSYPUFShCAAxQEVAYUBxQIGA0cABAQEBCOgA
MPJwWoCwWIoAQIRjAAAeZiFQsFEAGzBAcDYAQIRjAAAeAAAA/QAYeB7/dwAKICAgICAgAAAA/ABM
RyBUVgogICAgICAgAY4CA2rxXmFgdnVmZdvaEB8EEwUUAwISICEiFQFdXl9iY2Q/QDIPVwcVB1BX
BwFnBAM9HsBffgFuAwwAEAC4PCAAgAECAwRq2F3EAXiAYwIoeOIAz+MFwADjBg0B4g8z6wFG0AAq
GANRWZmqb8IAoKCgVVAwIDUAQIRjAAAeAAAA4A==

[Yabbie442]

I read this:  https://github.com/raspberrypi/firmware/issues/1648

Which you have commented on, and must be across popcornmix.  It sounds like the same thing I'm seeing (to my very untrained eye).

I suspect changing to the old fkms overlay will fix the problem (I'm guessing that's why Buster used to work), but I'd really prefer to get things working with the current/default/latest overlay.

Appreciate your help and patience.

[popcornmix]

Which you have commented on, and must be across popcornmix.  It sounds like the same thing I'm seeing (to my very untrained eye).

That issue includes the fatal "flip_done timed out". Does yours? Probably best to post your dmesg to a pastebin type site and link to it, rather than guessing.

[Yabbie442]

Which you have commented on, and must be across popcornmix.  It sounds like the same thing I'm seeing (to my very untrained eye).

That issue includes the fatal "flip_done timed out". Does yours? Probably best to post your dmesg to a pastebin type site and link to it, rather than guessing.

No, it doesn't look like it does include the fatal 'flip_done timed out", but the symptoms look similar, that was all I was trying to say.

Here is the dmesg output:  https://pastebin.com/DF3rFnW4

[popcornmix]

No, it doesn't look like it does include the fatal 'flip_done timed out", but the symptoms look similar, that was all I was trying to say.

Here is the dmesg output:  https://pastebin.com/DF3rFnW4

Doesn't look related. The linked issue occurred from boot (not on an AV input switch), and had different symptoms (from dmesg).

Your dmesg output had the problem occur too long ago, that any interesting messages have been lost due to the spammy "cec-vc4: message 10 timed out".
If you can boot, provoke the issue then capture dmesg output more quickly, there may be more useful information.

[Yabbie442]

Doesn't look related. The linked issue occurred from boot (not on an AV input switch), and had different symptoms (from dmesg).

Your dmesg output had the problem occur too long ago, that any interesting messages have been lost due to the spammy "cec-vc4: message 10 timed out".
If you can boot, provoke the issue then capture dmesg output more quickly, there may be more useful information.

Restarting the Kodi service 'fixes' the issue, and therefore, by extension, so does rebooting.

None the less, I rebooted, and got this:  https://pastebin.com/V5KuAKRf

[popcornmix]

If you can boot, provoke the issue then capture dmesg output more quickly, there may be more useful information.

I don't believe your dmesg was after provoking the issue.
I want to see signs of failure (e.g. "cec-vc4: message 10 timed out") plus whether there were any messages before that.

Also a debug enabled kodi log might be helpful (I suspect the issue will be kernel side, and so in dmesg, but we should check if kodi is reporting anything of interest).