RedGreen1
Posts: 3
Joined: Fri Jun 18, 2021 7:03 pm

Troubleshooting with 1680x1050 display output

Fri Jun 18, 2021 7:15 pm

I can't get my Pi to output natively to my 1680x1050 LCD monitor through HDMI. Changing hdmi_group=2 and hdmi_mode=58 added a 1680x1050 resolution setting under Screen Layout Editor. This displays a picture extending beyond the edges of the screen by around 50 pixels on all sides. Through trial and error, and lots of rebooting I'm close with the below overscan settings. Now I'm making 1 pixel edits and trying to judge how the cursor sits at each edge of the screen. Is there a better way to get this set up 1:1 with my monitor?

Could someone running with a 1680x1050 monitor please share your overscan settings with me? Thanks.

Pi 4 B/4GB
Pi OS 64-bit (updated)
HDMI to 1680x1050 LCD monitor
HDMI-1

/boot/config.txt
disable overscan=0
overscan left=61
overscan right=61
overscan top=46
overscan bottom=46
hdmi_group=2
hdmi_mode=58

*Edited overscan settings. I used sticky notes on the screen to line up pixel output.
Last edited by RedGreen1 on Sat Jun 19, 2021 7:34 pm, edited 1 time in total.

aBUGSworstnightmare
Posts: 3231
Joined: Tue Jun 30, 2015 1:35 pm

Re: Troubleshooting with 1680x1050 display output

Sat Jun 19, 2021 6:15 am

You're connected to HDMI0, the port closest ro the USB-C?

Can you please do some tests?
Disable your overscan settings and let KMS parse the EDID (and not the firmware). Add below to your config.txt

Code: Select all

 disable_fw_kms_setup=1  
i assume you're using FKMS graphic driver (which is the default on RPi4)? Do you have another uSD on hands which can be used for testing with the 32-bit OS?

I have some monitors where the EDID will not work on FKMS but they work perfectly fine under KMS. You may want to test as well, but be warned that some stuff may not work under KMS

RedGreen1
Posts: 3
Joined: Fri Jun 18, 2021 7:03 pm

Re: Troubleshooting with 1680x1050 display output

Sat Jun 19, 2021 6:57 pm

You're connected to HDMI0, the port closest ro the USB-C?
yes
Disable your overscan settings and let KMS parse the EDID (and not the firmware). Add below to your config.txt

Code: Select all

 disable_fw_kms_setup=1  
I disabled overscan and rebooted with the edited config.txt. It rebooted to 1280x720 and I no longer had the 1680x1050 resolution option in arandr.
i assume you're using FKMS graphic driver (which is the default on RPi4)? Do you have another uSD on hands which can be used for testing with the 32-bit OS?
This is a newly downloaded and updated image. I can easily put the 32-bit OS on an SD card or USB drive, although the 32-bit Pi OS and Ubuntu 21.04 64-bit give me the same default behavior.
I have some monitors where the EDID will not work on FKMS but they work perfectly fine under KMS. You may want to test as well, but be warned that some stuff may not work under KMS
I'll have to read up on these, thanks for your input.

aBUGSworstnightmare
Posts: 3231
Joined: Tue Jun 30, 2015 1:35 pm

Re: Troubleshooting with 1680x1050 display output

Sun Jun 20, 2021 6:49 am

RedGreen1 wrote:
Sat Jun 19, 2021 6:57 pm
You're connected to HDMI0, the port closest ro the USB-C?
yes
Disable your overscan settings and let KMS parse the EDID (and not the firmware). Add below to your config.txt

Code: Select all

 disable_fw_kms_setup=1  
I disabled overscan and rebooted with the edited config.txt. It rebooted to 1280x720 and I no longer had the 1680x1050 resolution option in arandr.
i assume you're using FKMS graphic driver (which is the default on RPi4)? Do you have another uSD on hands which can be used for testing with the 32-bit OS?
This is a newly downloaded and updated image. I can easily put the 32-bit OS on an SD card or USB drive, although the 32-bit Pi OS and Ubuntu 21.04 64-bit give me the same default behavior.
I have some monitors where the EDID will not work on FKMS but they work perfectly fine under KMS. You may want to test as well, but be warned that some stuff may not work under KMS
I'll have to read up on these, thanks for your input.
what is the output of below commands?

Code: Select all

tvservice -s
tvservice -m CEA
tvservice -m DMT 

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