Laptop not detecting external monitor

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andisk
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Laptop not detecting external monitor

Post by andisk »

I am using Mint 20 Ulyana/Win10 dual boot on my Lenovo Flex 5 laptop. I tried connecting to an external monitor using an HDMI cable but it is not detected. To check that there is no issue with the monitor or the cable, I tried the same thing logging in to windows 10 and it works fine.

Display settings in mint does not detect any external monitor.

My external monitor is DELL P2317H

How do I solve this issue?

Here is screenshot of xrandr -verbose

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andre@Flex-5-mint-pc:~$ xrandr --verbose
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 (0x3a5) normal (normal) 0mm x 0mm
	Identifier: 0x3a4
	Timestamp:  10707
	Subpixel:   unknown
	Clones:    
	CRTC:       0
	CRTCs:      0
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	non-desktop: 0 
		supported: 0, 1
  1920x1080 (0x3a5) 159.667MHz *current
        h: width  1920 start    0 end    0 total 1920 skew    0 clock  83.16KHz
        v: height 1080 start    0 end    0 total 1080           clock  77.00Hz
Screenshot of inxi -SGx

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System:
  Host: Flex-5-mint-pc Kernel: 5.4.0-42-generic x86_64 bits: 64 
  compiler: gcc v: 9.3.0 Desktop: Cinnamon 4.6.6 
  Distro: Linux Mint 20 Ulyana base: Ubuntu 20.04 focal 
Graphics:
  Device-1: AMD Renoir vendor: Lenovo driver: N/A bus ID: 04:00.0 
  Display: x11 server: X.Org 1.20.8 driver: ati,fbdev 
  unloaded: modesetting,radeon,vesa resolution: 1920x1080~77Hz 
  OpenGL: renderer: llvmpipe (LLVM 10.0.0 128 bits) v: 3.3 Mesa 20.0.8 
  direct render: Yes 
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roblm
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Re: Laptop not detecting external monitor

Post by roblm »

From looking at your other topic, you have very new hardware. The Ryzen 7 4700U CPU launched on 1-6-20. User ficus2 in this topic has a similar Ryzen 7 4800U which has the same launch date. He had to install the 5.7.1 kernel for better support:
viewtopic.php?f=59&t=325007

This may fix both your monitor detection and brightness problems. You can install Ukuu to make the kernel installation easier. The latest version of Ukuu now requires purchasing a license for $11, but you can get an older version here:
https://github.com/teejee2008/ukuu/releases

Download the ukuu-v18.9.1-amd64.deb file.
andisk
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Re: Laptop not detecting external monitor

Post by andisk »

Hi Roblm,

Thank you so much for your reply. I managed to do all of your instructions and I had the external monitor working.

However, the brightness level adjustment is still not working.

Thanks alot.
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roblm
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Re: Laptop not detecting external monitor

Post by roblm »

Check Keyboard settings. The Fn key may not be assigned to screen brightness.

Use this command and post the output:

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sudo strings /sys/firmware/acpi/tables/DSDT | grep -i 'windows ' | sort
andisk
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Re: Laptop not detecting external monitor

Post by andisk »

Here is the ouput

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]andre@Flex-5-mint-pc:~$ sudo strings /sys/firmware/acpi/tables/DSDT | grep -i 'windows ' | sort

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[sudo] password for andre:     
Microsoft Windows NT
Windows 2001
Windows 2001.1
Windows 2001 SP1
Windows 2001 SP2
Windows 2001 SP3
Windows 2006
Windows 2006 SP1
Windows 2009
Windows 2009
Windows 2012
Windows 2013
Windows 2015
Windows 2015
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roblm
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Re: Laptop not detecting external monitor

Post by roblm »

Use this comand to open the grub file: xed admin:///etc/default/grub

Change this line:

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GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
To this:

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GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=! \"acpi_osi=Windows 2015\""
Then update grub: sudo update-grub

What that does is enable the OS to report it is Windows instead of Linux. On some laptops, the BIOS checks to see if Windows is installed. If not, then some laptop functions may be disabled or not work well.

Reboot. If that doesn’t help, then change the line to this and update grub:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=! \"acpi_osi=Windows 2012\""

If that fails, try this line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=! \"acpi_osi=Windows 2009\""

If that fails, then try these parameters:

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acpi_backlight=vendor
acpi_osi=Linux
acpi_osi=Linux acpi_backlight=vendor
video.use_native_backlight=1
acpi_osi=
andisk
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Re: Laptop not detecting external monitor

Post by andisk »

I tried windows 2015 and 2012. Neither of them worked
windows 2009 - touchpad did not work so I turned it back to 2015

when I tried this

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acpi_backlight=vendor
acpi_osi=Linux
acpi_osi=Linux acpi_backlight=vendor
video.use_native_backlight=1
acpi_osi=


this gave me error as shown

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 sudo update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/50_linuxmint.cfg'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.7.1-050701-generic
Found initrd image: /boot/initrd.img-5.7.1-050701-generic
Found linux image: /boot/vmlinuz-5.4.0-42-generic
Found initrd image: /boot/initrd.img-5.4.0-42-generic
Found linux image: /boot/vmlinuz-5.4.0-26-generic
Found initrd image: /boot/initrd.img-5.4.0-26-generic
Found Windows Boot Manager on /dev/nvme0n1p1@/EFI/Microsoft/Boot/bootmgfw.efi
Adding boot menu entry for UEFI Firmware Settings
error: syntax error.
error: Incorrect command.
error: syntax error.
Syntax error at line 286
Syntax errors are detected in generated GRUB config file.
Ensure that there are no errors in /etc/default/grub
and /etc/grub.d/* files or please file a bug report with
/boot/grub/grub.cfg.new file attached.
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roblm
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Re: Laptop not detecting external monitor

Post by roblm »

You must have made an error in editing the grub file. Test this line first:

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GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
If that doesn’t help, then remove acpi_backlight=vendor and test these parameters, one at a time:

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acpi_osi=Linux
acpi_osi=Linux acpi_backlight=vendor
video.use_native_backlight=1
acpi_osi=

If that doesn’t help, then iInstall xbacklight: apt install xbacklight

Test using these commands:

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xbacklight -set 50             Range is 5-100
xbacklight -inc 40             increase brightness by 40%
xbacklight -dec 40             decrease by 40%

If that fails, then try using the Brightness Confroller program:
http://ubuntuhandbook.org/index.php/201 ... 04-higher/

Add the PPA. The program will be added to the menu under the Accessories category.


If that fails, then post the output of this command: ls /sys/firmware
andisk
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Re: Laptop not detecting external monitor

Post by andisk »

Code: Select all

acpi_backlight=vendor			 ---> Did not work
acpi_osi=Linux				 ---> Did not work				
acpi_osi=Linux acpi_backlight=vendor 	 ---> Did not work
video.use_native_backlight=1	 	---> Did not work
acpi_osi=				---> error see below attachment 
xbacklight ---> did not work

PPA brightness controller seems to be working.

Although I am able to adjust the brightness of my screen using PPA brightness controller, I am still curious why GRUB_CMDLINE_LINUX_DEFAULT parameters did not work.

In case if you are still wondering the output of

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andre@Flex-5-mint-pc:~$ ls /sys/firmware 
acpi dmi efi memmap
Attachments
01e38fcf-53cc-4f69-b5af-110be29450d0.jpg
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