welshgeekboy
Posts: 24
Joined: Wed Feb 17, 2016 8:59 am
Location: Wales, Carmarthenshire

Open GL driver overrides screen size settings?

Mon Jun 13, 2016 1:55 pm

Hi, I've just started using the Open GL driver on my Pi 3. It seems to override settings in /boot/config.txt file? I have four settings that make the Pi output correctly for my HDMIPi regarding screen size (1280x800) etc. and when the driver is enabled the output screen resolution is 1920x1080. I want to be able to use the settings I've written in /boot/config.txt but also use the Open GL driver. If possible I want it to be easy to enable and disable the driver (like commenting out a line in the config file) but all other settings stay the same.

Is there a way to do this? Primarily I want 1280x800 with the Open GL driver enabled.

Here is the contents of my /boot/config.txt file:

Code: Select all

# /boot/config.txt
# For more options and information see
# http://www.raspberrypi.org/documentation/configuration/config-txt.md

# Miscellaneous
disable_overscan=1
#gpu_mem=128
dtoverlay=vc4-kms-v3d
dtparam=audio=on
#disable_audio_dither=0

# HDMIPi settings
hdmi_ignore_edid=0xa5000080
hdmi_group=2
hdmi_drive=2
hdmi_mode=28
Thanks all.
Pi B r2, Pi Zero (no cam), Pi 3, acid yellow HDMIPi, lots of robot bits.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: Open GL driver overrides screen size settings?

Mon Jun 13, 2016 2:21 pm

Everything in config.txt is parsed by the GPU firmware. The only bit that then gets passed on to the kernel is the device tree (ie any dtoverlay and dtparam lines).

The OpenGL driver is solely a kernel driver, directly driving the composition hardware, so it knows nothing about any of those settings. That is the expected behaviour.
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rpiMike
Posts: 1335
Joined: Fri Aug 10, 2012 12:38 pm
Location: Cumbria, UK

Re: Open GL driver overrides screen size settings?

Mon Jun 13, 2016 5:17 pm


welshgeekboy
Posts: 24
Joined: Wed Feb 17, 2016 8:59 am
Location: Wales, Carmarthenshire

Re: Open GL driver overrides screen size settings?

Mon Jun 13, 2016 7:27 pm

Thanks both, this sounds promising. I'll try what you say. Editing /boot/cmdline.txt sounds like it ought to work.
Pi B r2, Pi Zero (no cam), Pi 3, acid yellow HDMIPi, lots of robot bits.

welshgeekboy
Posts: 24
Joined: Wed Feb 17, 2016 8:59 am
Location: Wales, Carmarthenshire

Re: Open GL driver overrides screen size settings?

Tue Jun 14, 2016 7:49 pm

Okay, with

Code: Select all

video=1280x800
added to the end of the single line in /boot/cmdline.txt, the Pi boots with no change (screen output resolution is still 1920x1080) except at no point is the console displayed. I have the Pi boot to desktop so I can see the destop, but during boot and if I change (I apologise if I use the wrong language here) to a console (tty1 to tty6) using Ctrl+Alt+(F1 to F6) then the screen does not show anything and gives a warning saying the signal is out of range. So the cmdline.txt option has not worked for me.

Do you have any other suggestions? Thanks again.
Last edited by welshgeekboy on Wed Jun 22, 2016 6:44 am, edited 1 time in total.
Pi B r2, Pi Zero (no cam), Pi 3, acid yellow HDMIPi, lots of robot bits.

welshgeekboy
Posts: 24
Joined: Wed Feb 17, 2016 8:59 am
Location: Wales, Carmarthenshire

Re: Open GL driver overrides screen size settings?

Wed Jun 22, 2016 6:40 am

OK, a little update- with or without the driver enabled, the Pi didn't show any of the booting text. The only thing it showed was the log in text before it loaded X. I changed the option in the Raspberry Pi Configuration menu to disable sending messages as the Pi boots over serial and now all the boot text is shown on the screen as the Pi boots. I have not tried with the driver enabled, but the point is the lack of boot text was not a result of the driver. Just a setting in the configuration needed to be toggled. It's worth mentioning that I don't think I enabled serial messages- I don't remember doing it at least.
Pi B r2, Pi Zero (no cam), Pi 3, acid yellow HDMIPi, lots of robot bits.

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