DTOVERLAY setting in config.txt preventing Libreelec 10 RC1 from starting

justchekin · August 10, 2021 at 7:52 PM

Hello,

I'm using a 4GB RPI4 with the official 7 inch touchscreen (in a Smartipi case). In prior test builds of LibreElec 10 with this setup, I've had to add a setting to config.txt to get the OS to recognize the touchscreen, and even then it works intermittently. That setting is the following:

dtoverlay=vc4-kms-dsi-7inch

Without this setting in config.txt, the touchscreen display will not show anything in the prior LibreElec 10 test builds.

When upgrading to LibreElec 10 RC1, I've learned that if this setting is added to config.txt, LibreElec will not load. Is there a workaround to implementing this dtoverlay setting in a way that will allow LibreElec 10 RC1 to load properly?

Thanks.

**HiassofT** · August 10, 2021 at 8:39 PM

The kms driver for the official 7" display is still WIP and has several known issues. See eg here Full KMS does not work with pi4 and official touchscreen on kernel 5.10.1 · Issue #4020 · raspberrypi/linux · GitHub - RPi forum also has a couple of threads about it, eg this one RPi3 / VC4 KMS driver / 7" display = blank - Raspberry Pi Forums

so long,

Hias

justchekin · November 12, 2021 at 2:08 AM

As a follow-up, FYI, I attempted LibreElec 10.0.1 with the official 7" display. Same exact issues occur that i reported earlier in the thread relating to LibreElec 10 RC1.

**HiassofT** · November 12, 2021 at 7:57 PM

Please give this build a try: https://www.horus.com/~hias/tmp/libr…232-e829476.tar (just copy it to the update share and reboot)

I noticed we were missing some kernel config options, they are included in this build.

so long,

Hias

justchekin · November 13, 2021 at 4:22 AM

I tried the above build. With this version, if dtoverlay=vc4-kms-dsi-7inch is added to config.txt, there's no display, and LibreElec doesn't start up (verified by not being able to ping the device nor access the device's shared network folders). Also, if the above dtoverlay command is removed from config.txt, there too is no display, but LibreElec does start up (verified by being able to ping the device and being able to access the device's shared network folders).

**HiassofT** · November 13, 2021 at 6:43 PM

Next try, could you please test with this build: https://www.horus.com/~hias/tmp/libr…536-90f3d53.tar

I found a couple more modules need to be built into the kernel.

so long,

Hias

justchekin · November 13, 2021 at 10:57 PM

I just tried this build also. Same symptoms as with the prior test build. If dtoverlay=vc4-kms-dsi-7inch is added to config.txt, no display, and no start up of LibreElec (can't ping the device nor access the device's shared network folders). If the above dtoverlay command is removed from config.txt, no display, but LibreElec does start up (device can be pinged and the shared network folders can be accessed). One other thing as well because I don't know if this might have any relevance. Earlier in the thread, another thread was referenced, and I looked at recent changes in the other referenced thread. It made mention of a command added in config.txt in the bullseye version of Raspberry Pi OS. That command is display_auto_detect=1. It mentions that for that OS, if this command is active in config.txt, the firmware would automatically check for the official 7" display and, if detected, automatically load the vc4-kms-dsi-7inch overlay. I tried adding that command in place of the above dtoverlay command in config.txt for these two test builds of LibreElec just to see what would happen. No display, and LibreElec doesn't start up (can't ping the device nor access the device's shared network folders).

**HiassofT** · November 13, 2021 at 11:07 PM

Thanks for testing!

The main problem with the DSI drivers is that the kernel ends up in an endless probe loop if something is wrong (eg a driver missing or not initializing) without telling you what failed - several drivers just silently pass on errors without logging anything so there's no chance of finding out which of the sub-sub-sub components are missing or failing to initialize.

I get the same lockup (endless probe/bind loop) here with the 7inch dtoverlay loaded. I don't have the display, so I'd expect things to fail, but not as badly as they do (unable to complete kernel boot) and tons of meaningless errors on the serial console.

At the moment I'm at a complete loss, I think I have all the required dependencies enabled and no idea what else might be missing.

so long,

Hias

**HiassofT** · November 14, 2021 at 2:02 PM

New day, new try - I noticed I missed one option: https://www.horus.com/~hias/tmp/libr…442-9bbb99c.tar

Please report back if it works. If it doesn't please post your config.txt (Note that IIRC you need to have ignore_lcd=1 in it, and the 7inch dtoverlay after the "include distroconfig.txt").

so long,

Hias

justchekin · November 15, 2021 at 7:36 PM

I just tried the new test build. Much, much better! The 7" display works on each startup.

FYI, these are the two settings I've had in my config.txt file (already positioned after "include distroconfig.txt")....

dtoverlay=vc4-kms-dsi-7inch

dtparam=audio=on

Also, the display works on each startup regardless of whether or not ignore_lcd=1 is included in config.txt.

Thank you so much for all your help!

**HiassofT** · November 16, 2021 at 4:52 PM

Thanks a lot for testing, it's great this is working now - this was a tough puzzle to solve

We'll include the necessary config changes in LE so future LE versions will support the official 7inch display.

so long,

Hias

Ensoft · December 4, 2021 at 5:16 PM

Quote from HiassofT

Thanks a lot for testing, it's great this is working now - this was a tough puzzle to solve
We'll include the necessary config changes in LE so future LE versions will support the official 7inch display.
so long,
Hias

Hi,

Do you know when necessary config changes will be integrated in LibreELEC?

I just downloaded the lastest stable version but the display locks on a greyish splash screen.

Or do I need to make some changes to the config.txt file?

malorter · December 20, 2021 at 8:45 PM

Hi, I'm facing the same issue descibed above. I tried the latest stable (display not working) and the latest nightly (display not working). If I copy the files from the tar to the sd card, it says operating system not found. I'm not able to flash it. It would be great to see your improvments implemented in the official build. Thanks

**HiassofT** · December 20, 2021 at 9:01 PM

The changes are included in nightly builds for a while now so it should work - but keep in mind we can't test it as we don't have the necessary hardware.

So if it doesn't work please do a clean install of latest nightly first and post details (logs, etc).

Feedback if it works with latest nightly would be good, too

so long,

Hias

malorter · December 21, 2021 at 6:53 PM

Hi, thanks for the quick answer. I got a little further, however it's not working yet.

My hardware:

- Raspberry Pi 4 2GB

- official Raspberry Pi 3 7" Touchscreen Display

- 5 V 3A power supply through the display

- HDMI Monitor with Micro HDMI to HDMI cable

- Plugged in network cable

- wireless USB keyboard

What I tried:

With the latest nighty build (20211220):

1. Old install, standard config, hdmi: Touchscreen pulsing grey, hdmi showing splash screen then dying

2. Fresh install, standard config, hdmi: Both screens show rainbow, partition resizing, restart, both screens show rainbow, hdmi dying, touchscreen pulsing grey.

3. Edit to 2.: edited config dtoverlay=vc4-kms-dsi-7inch: Both hdmi and touchscreen showing rainbows, hdmi dying, libreelec splash screen (showing version) on touchscreen, no further boot

4. Edit to 3: With ignore_lcd=1: No rainbows, hdmi dying, touchscreen stuck on splash screen as in 3

5. Fresh install, config with dtoverlay=vc4-kms-dsi-7inch: ignore_lcd=1: no rainbows, resizing, restart, short rainbow on on hdmi, both showing libreelec splash screen, hdmi dying, libreelec splash screen stays on touchscreen as in 3.

6. Edit to 5: Config with dtoverlay=vc4-kms-dsi-7inch, dtparam=audio=on, hdmi not inserted: : Rainbow, boot, touchscreen is working, no touch. After restart: stuck on splash screen as in 3.

7. Tried to reproduce, fresh install with no hdmi, dtoverlay=vc4-kms-dsi-7inch, dtparam=audio=on: Rainbow, resize, reboot, rainbow, stuck on splash screen.

I don't know what I did right in 6 but I don't manage to reproduce it even when I involve step 5.

To sum it up: The screen itself is working, but the boot is stuck almost every time on the splash screen (Libreelec version screen).

Please let me know if can be any help in working it out.

My config when edited:

Code

# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (C) 2009-2014 Stephan Raue (stephan@openelec.tv)
# Copyright (C) 2016-present Team LibreELEC (https://libreelec.tv)
################################################################################
# Bootloader configuration
# config.txt version v1 (do not remove or change this line!)
################################################################################
# For more options and information see
# http://rpf.io/configtxt
################################################################################


# Default GPU memory split, 76MB are needed for H264 decoder
gpu_mem=76


# Don't send initial active source message.
# Avoids bringing CEC (enabled TV) out of standby and channel switch when
# rebooting.
hdmi_ignore_cec_init=1


################################################################################
# Include distribution specific config file if it exists.
################################################################################
[all]
include distroconfig.txt
dtoverlay=vc4-kms-dsi-7inch
dtparam=audio=on


# uncomment to enable infrared remote recevier connected to GPIO 18
#dtoverlay=gpio-ir,gpio_pin=18

Display More

I tried OSMC as well and it has a similar problem. Even if the Screen is working out of the box on the first startup it gets grey later on. I can access the system via HDMI but I can't switch to Touchscreen. With dtoverlay=vc4-kms-dsi-7inch and dtparam=audio=on no screen is working anymore. Ubuntu server is working out of the box (screen, don't know how to test touch here), Ubuntu Desktop ist not working (grey screen) and raspberry pi os is working after adding dtoverlay=vc4-kms-dsi-7inch and ignore_lcd=1 to the config (touch seems to be locked there - can perform one touch and nothing more - maybe a screen issue?).

malorter · December 23, 2021 at 8:20 PM

Since I suspected my touchscreen of a physical malfunction I called my retailer and he told me about known issues after a major update for Raspberry Pi 4. So touch is supposed to be not working on any system at the moment however the screen preventing Libreelec from booting seems to stay a specific problem with Libreelec and Raspberry Pi 4. I could "solve" this by disabling the kms driver in Rapberry Pi OS.