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Pi 4, Display - No Input, hdmi_safe=1, irregular green blinks

Posted: Tue Dec 03, 2019 1:17 am
by AggroFrizzy
Hello!

I've tried changing hdmi_safe to 1 in the conf. All I get is no signal on a 4k ultrawide. It is interesting that my monitor will have been running for some time with a black screen, and a bit after I turn on the Pi it will pop up with 'No Signal.' So it seem slike it's making some sort of attempt, maybe??

The green light is active for some time with rapid blinking with the SD card in, but eventually it justs stays red (sleeping?). Without the SD card it stays green for a few moments, and then proceeds to blip on a few times followed by a pause, followed by more blips and pauses.

Not sure what else to try! The wiki seems to state that hdmi boost doesn't do anything on the raspberry pi 4. Any ideas?

edit: title says no input, but it's no signal - not that it makes a difference

Re: Pi 4, Display - No Input, hdmi_safe=1, irregular green blinks

Posted: Tue Dec 03, 2019 7:13 am
by renice123
If the green LED is blinking (randomly), then this is very good. This means that your Raspberry is working and loading the operating system. But since you changed the display settings in config.txt, then Raspberry can not configure hdmi. The fourth version works differently than the third version of Raspberry - RPI4 tries to read data from the display and if it does not arrive (as in your case due to an erroneous configuration of config.txt), then the display does not work. The config.txt file in the video part allows you to more or less flexibly configure hdmi, but in your case, the easiest way is to return the old settings and check the monitor. Unless, of course, you set the goal of an experiment with a headless raspberry

Re: Pi 4, Display - No Input, hdmi_safe=1, irregular green blinks

Posted: Tue Dec 03, 2019 2:45 pm
by AggroFrizzy
I tried changing the config.txt after nothing came up on the display besides 'no signal.'

I've been able to SSH in at least now.

What else can I try?

Re: Pi 4, Display - No Input, hdmi_safe=1, irregular green blinks

Posted: Wed Dec 04, 2019 7:15 pm
by renice123
You can try replacing the hdmi cable to the monitor. Sometimes it helps. Do you connect the monitor to the first hdmi output?
There is another interesting feature of Raspberries of the fourth version: first you need to turn on the monitor, and then turn on the Raspberries. Otherwise, Raspberry will not receive the EDID from the monitor.
Try rewriting the image of the Rasbian from scratch to a blank card. Maybe somewhere on the card there is an error

Re: Pi 4, Display - No Input, hdmi_safe=1, irregular green blinks

Posted: Wed Dec 04, 2019 8:23 pm
by FTrevorGowen
renice123 wrote:
Wed Dec 04, 2019 7:15 pm
...
There is another interesting feature of Raspberries of the fourth version: first you need to turn on the monitor, and then turn on the Raspberries.
...
That's always been the preferred approach for all Pi's connected to a display (ie. not P4 specific but, since edid handling etc. has changed with Buster, it might seem to be the case). Some displays need to be "pre-set" to the correct input as well.
@AggroFrizzy, since you can SSH in to your P4 can you post the output of these tvservice commands please (after cleaning up the config.txt file perhaps)?

Code: Select all

tvservice -n
tvservice -m DMT
tvservice -m CEA
tvservice -s
Hopefully we'll glean a clue or two from that info.
Trev.