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Trouble Getting HDMI Output From RPi4

Posted: Thu Jun 27, 2019 8:34 pm
by Mortimer
I am having trouble getting HDMI output from my new RPi4. I am able to get to it via SSH, so would appear to be working. The display (Motorola Atrix Lapdock) is not complaining that there is no signal, which it does if I switch the connection to the HDMI-1 port. So I presume there is a signal there, but the lap dock is not displaying it.

I tried the following:

hdmi_force_hotplug:0 = 1
hdmi_group:0 = 2
hdmi_mode:0 = 39

The lap dock now displays the four raspberries, then it blanks with a flashing cursor. I will get a brief flash of the splash screen (less than a second) a few more seconds of flashing cursor then the screen goes completely black and nothing further is displayed.

Any ideas?

Re: Trouble Getting HDMI Output From RPi4

Posted: Thu Jun 27, 2019 8:42 pm
by scotty101
I'm having a similar issue. I'm using a Nexdock and have also tried it with my TV.
HDMI signal seems to be recognised because the HDMI port shows as available on the TV and the Nexdock doesn't shutdown (normally does when it has no input signal).
I was wondering if the microHDMI cable was the problem but I doubt it given that something like a signal seems to get through. Any thoughts for diagnosing the problem?

EDIT: In fact exactly the same problem. Tried the same settings as you and now I get the rainbow test screen, 4 raspberries, a flashing cursor and then nothing. At least I can rule out the cable now.

Re: Trouble Getting HDMI Output From RPi4

Posted: Thu Jun 27, 2019 10:13 pm
by Mortimer
Sort of comforting to know that I am not alone with this problem.
Would be nice to find a solution.

I wish the RPi had a feature like my Apple TV. A button combination puts it into a mode where it can be stepped through all available display modes one-by-one by clicking a button. Naturally you stop when you find one that brings the screen to life.

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 7:50 am
by scotty101
I tried many different HDMI modes last night both on my Nexdock and on my Samsung TV and had no success.

Very strange....

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 9:31 am
by jamesh
We are looking in HDMI problems right now. Some we have been able to replicate which helps!!

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 9:45 am
by scotty101
jamesh wrote:
Fri Jun 28, 2019 9:31 am
We are looking in HDMI problems right now. Some we have been able to replicate which helps!!
Are they hardware or software related?
Do I need to return this Pi while it is still within the returns policy?

tvservice -o "turns off" the screen
tvservice -p "turns on" the screen but the screen is still blank.

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 10:40 am
by jamesh
scotty101 wrote:
Fri Jun 28, 2019 9:45 am
jamesh wrote:
Fri Jun 28, 2019 9:31 am
We are looking in HDMI problems right now. Some we have been able to replicate which helps!!
Are they hardware or software related?
Do I need to return this Pi while it is still within the returns policy?

tvservice -o "turns off" the screen
tvservice -p "turns on" the screen but the screen is still blank.
Software.

That's expected behaviour for tvservice - it turns everything off, which indirectly causes the framebuffer to be dealloacted, but when turned back on the framebuffer is not recreated. IIRC, use fbset to then recreate a frame buffer.

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 10:41 am
by jamesh
Mortimer wrote:
Thu Jun 27, 2019 8:34 pm
I am having trouble getting HDMI output from my new RPi4. I am able to get to it via SSH, so would appear to be working. The display (Motorola Atrix Lapdock) is not complaining that there is no signal, which it does if I switch the connection to the HDMI-1 port. So I presume there is a signal there, but the lap dock is not displaying it.

I tried the following:

hdmi_force_hotplug:0 = 1
hdmi_group:0 = 2
hdmi_mode:0 = 39

The lap dock now displays the four raspberries, then it blanks with a flashing cursor. I will get a brief flash of the splash screen (less than a second) a few more seconds of flashing cursor then the screen goes completely black and nothing further is displayed.

Any ideas?
Does the output work when plugged in to a normal HDMI equipped monitor or TV? (I'm presuming the lapdock this is some sort of HDMI->LCD system?)

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 10:46 am
by scotty101
Can't speak for Mortimer but it didn't work on my Samsung TV nor the Nexdock*.

*It's just a HDMI to LCD packaged with a screen, bluetooth keyboard and trackpad and has worked with everything from the original Pi to the Pi3B+.

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 10:47 am
by goodburner
I was having similar issues where it wouldn't boot if I enabled some options like VNC, Serial Port, Serial Console, overclock GPU memory, etc.. I was able to fix this by setting

confIg_hdmi_boost to 7.

At least I think so, I'm upgrading packages right now and will report if it is successful.

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 10:50 am
by scotty101
goodburner wrote:
Fri Jun 28, 2019 10:47 am
I was having similar issues where it wouldn't boot if I enabled some options like VNC, Serial Port, Serial Console, overclock GPU memory, etc.. I was able to fix this by setting

confIg_hdmi_boost to 7.

At least I think so, I'm upgrading packages right now and will report if it is successful.
Will give this a try later too. I may be going crazy but I thought I had read that hdmi_boost didn't work with the Pi4.

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 11:19 am
by goodburner
after upgrading the packages it went blank again after showing the cursor at the top left like before.
I had to disable vnc and serial port/console again and noticed the screen was set to 4k while I had it at 1080p previously.
it seems to be working now.


I'm not sure why these weren't caught before releasing the device. :roll:

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 11:28 am
by tvjon
scotty101 wrote:
Fri Jun 28, 2019 9:45 am
...Do I need to return this Pi while it is still within the returns policy?
..

From my limited exposure to Pi4 so far (thanks to UPS) I'd say it's extremely unlikely to be the Pi4.

You mention "Samsung TV". Does this TV have a composite input? Thanks to UPS again, I've initially used a 4 on a Samsung TV/monitor's composite input . Pi4's Composite output is very good BTW, no dot crawl visible on this setup here.

Also, can you ssh into your pi (via ethernet as you won't have been able to setup wifi) from say a previous PI, or some other computer?

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 11:36 am
by procount
@Mortimer - I will try my Pi4 on my Lapdock for comparison, if I can get hold of the right HDMI cable - never thought to do that.

How are you powering it - via separate USB-C power adaptor? If so, be careful not to power the Lapdock at the same time from a separate power supply. I tried that before and blew up 2 Lapdocks in the process! Maybe it's different with the Pi4 but I wouldn't chance it.

I tried my Pi4 on a HDMIPI and a Samsung TV via HDMI. Both work ok.
The config.txt video settings are now only used for console mode. You could try booting to the console instead of the desktop to figure out what settings are needed. But then they need to be entered separately for the desktop.
For my HDMIPI it was necessary to add "hdmi_ignore_edid=0xa5000080" to allow the screen configurator to select the correct mode.

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 11:57 am
by jamesh
goodburner wrote:
Fri Jun 28, 2019 11:19 am
after upgrading the packages it went blank again after showing the cursor at the top left like before.
I had to disable vnc and serial port/console again and noticed the screen was set to 4k while I had it at 1080p previously.
it seems to be working now.


I'm not sure why these weren't caught before releasing the device. :roll:
Because some bugs only show up after launch? Impossible to test every single TV/Monitor/HDMI convertor, and even with the larger beta test program we used this time, you cannot catch everything.

I see from your previous post that you overclocked the GPU memory. That will almost certainly cause problems, all bets are off when overclocking. We won't have caught that in testing, because it's not a supported feature.

IIRC, hdmi_boost is not used on the Pi4. It has a different HDMI HW block, and the boost feature is not available. I am going to check that is right though, once the guy who knows about it gets back from Glastonbury!

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 12:04 pm
by k-pi
once the guy who knows about it gets back from Glastonbury!
But will he be able to hear your questions........ :lol:

Re: Trouble Getting HDMI Output From RPi4

Posted: Fri Jun 28, 2019 12:26 pm
by scotty101
tvjon wrote:
Fri Jun 28, 2019 11:28 am
You mention "Samsung TV". Does this TV have a composite input? Thanks to UPS again, I've initially used a 4 on a Samsung TV/monitor's composite input . Pi4's Composite output is very good BTW, no dot crawl visible on this setup here.
Not a solution to the HDMI problem. Whilst my TV has a composite input, i don't have the correct cable and the normal screen I use with Pi's is the Nexdock (more portable)
tvjon wrote:
Fri Jun 28, 2019 11:28 am
Also, can you ssh into your pi (via ethernet as you won't have been able to setup wifi) from say a previous PI, or some other computer?
I have been able to SSH in to the Pi. I setup WiFi/SSH on a Pi3. This gave me the ability to run the tvservice command to try a few things as well as change the config.txt file and safely shutdown the Pi

Re: Trouble Getting HDMI Output From RPi4

Posted: Sat Jun 29, 2019 12:02 am
by kentisevil
well I also am having a problem - I thought it was my card or maybe the RPI4-

installed buster - full desktop - dropped the wpa-supplicant and ssh files in boot - rebooted - no signal on my 32" ONN tv from walmart

was able to ping from my ubuntu box - ssh'd in - rebooted again

no - dice so I 'thought' maybe I DL'd headless - and maybe the console output is off???? don't know so I reflashed (on a different card) and booted again - no signal

went through my TV settings and 'scanned' the hdmi inputs - it saw my roku and the raspberry pi..... cool

so now I set up the power on feature blah blah blah

rebooted again

no dice - figured okay maybe it is a resolution thing - let me try a monitor - bada bam - worked fine booting and plugged into my dell 24" monitor via DVI - HDMI adapter (the same one I use for mu NUC's)

great - I set the resolution to 1024 x 768 and flipped the cables - BAM I can now see my screen on my TV

Reboot - nothing - no dice nothing at all

put the cables back boot - I can see the 4 raspberrys the boot then desktop on the Dell monitor

put them the other way neither display lights up

when the cables are in the Dell = HDMI0 and ONN=HDMI1 - I get video on the dell but nothing shows up on the ONN TV

when I boot with one cable in on the ONN = HDMI0 - nothing - however I can ssh into the RPI

when I boot with one cable in on the dell = HDMI0 - seems fine

so frustrating that I can't 'nail' this up and just use it on the tv (obliviously the dell doesn't have speakers)

Re: Trouble Getting HDMI Output From RPi4

Posted: Sat Jun 29, 2019 12:23 pm
by m4r35n357
New RPi 4 arrived today. Unfortunately I am getting a display which is slightly too big for the "standard" screen resolution (1920*1080). it makes the menu very hard to operate. I have tried to make various changes (overscan settings, manual HDMI mode setting) in config.txt, but they only seem to apply to the framebuffer at boot, not the desktop screen.

BTW I am an "experienced" RPi user, since v1., and I usually have to adjust these settings and they usually fix things. This is the first time I have been unsuccessful, and the first time I have seen config.txt settings make no difference. I can only therefore assume this is a bug. Is anyone else seeing this?

Re: Trouble Getting HDMI Output From RPi4

Posted: Sat Jun 29, 2019 12:27 pm
by procount
I think it has been stated elsewhere that the overscan settings are currently ignored for the new KMS display drivers, but they are looking into it.

Re: Trouble Getting HDMI Output From RPi4

Posted: Sat Jun 29, 2019 12:30 pm
by PeterO
I'm finding it difficult to get my twin headed PI4 to boot properly. It seems very sensitive to the power state of the monitors when the Pi is turned on.
PeterO

Re: Trouble Getting HDMI Output From RPi4

Posted: Sat Jun 29, 2019 1:37 pm
by FTrevorGowen
procount wrote:
Sat Jun 29, 2019 12:27 pm
I think it has been stated elsewhere that the overscan settings are currently ignored for the new KMS display drivers, but they are looking into it.
+1 I've had the same issue and logged it. AIUI it's more to do with Buster/current kernel etc. than a "P4B thing" (ie. it happened with Buster on a Pi B2 too) and is worse with TV's / CEA modes. (IIRC EDID info. not being passed fully in some cases). Ironically, IIRC, I got a "better" result via an HDMI-to-VGA converter and a VGA input which used a (reduced) set of DMT (cf. CEA) modes.
Trev.

Re: Trouble Getting HDMI Output From RPi4

Posted: Sat Jun 29, 2019 3:14 pm
by scotty101
I'm having some success but success with a black border.

I've got the following settings in /boot/config.txt

Code: Select all

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
#dtoverlay=vc4-fkms-v3d
max_framebuffers=2
hdmi_force_hotplug:0=1
#hdmi_safe=1
hdmi_group:0=1
hdmi_mode:0=4
Disabling the vc4 V3D driver seems to have had a positive effect.

Re: Trouble Getting HDMI Output From RPi4

Posted: Sat Jun 29, 2019 5:40 pm
by shards127
I was having very similiar problems with Pi 4 connecting HDMI to VGA, text was fine but desktop didn't load. I tried all the suggested fixes with no success. I then, in desperation, commented out the dta_overlay line in the pi 4 section of the config file and all works fine - no other changes from default needed. I guess I may not be able to run 2 screens at 4k simultaneously but that wasn't in my game plan anyway.

Re: Trouble Getting HDMI Output From RPi4

Posted: Sun Jun 30, 2019 3:28 pm
by mr_bub
Exactly the same issue here. Had to buy new hdmi cables due to the size of the connectors and now monitor says “ No Signal from Current Input”.

Very annoying as I already had to wait for cables abs now I still have nothing. All of my other Pis work fine - new version clearly poorly thought out in respect of connectivity.