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gpio display and hdmi display

Posted: Tue Mar 31, 2015 10:26 pm
by brainbuddy
Hello

first off I want to say Hi! I'm new here to the forum and I'm new to the raspberry pi

I got the raspberry pi b2 and I wanted to create a portable and main game station from it.
so that I can play games on the bus and with a bigger screen home.

but for this I got a little question:
if I got an GPIO display plugin in the board and also plugin a monitor trough HDMI what will happen ?
will the display "mirror" each other or do I got 2 displays then or will the display on the HDMI/GPIO not work?

Re: gpio display and hdmi display

Posted: Tue Mar 31, 2015 10:55 pm
by MarkHaysHarris777
I got the raspberry pi b2 and I wanted to create a portable and main game station from it; so that I can play games on the bus and with a bigger screen home.
Really. Which screen are you going to use? How are you going to power it? Do you have a case for it already, or are you planning to print one on your 3D printer? What games do you plan to play on it?

Do you have an RPi 2, or do you have an RPi b+, or do you have an RPi 2B ?

Inquiring minds want to know.

(oh, almost forgot, it will be YOUR project; you tell the screens to do what YOU want them to do)

Re: gpio display and hdmi display

Posted: Wed Apr 01, 2015 1:49 am
by AndyD
The screens that plug into the GPIO provide a second framebuffer (if they are supported by the kernel module written by Notro and now available in the Raspbain kernel). So by default nothing it displayed on these GPIO displays.

Not everything displayed on the Raspberry Pi screen uses the framebuffer. Things like Minecraft and the GPU accelerated video player don't use the framebuffer and so can't (easily) be displayed on a GPIO display.

There is a program called fbcp that will copy everything on the Raspberry Pi display (I also wrote a similar program recently with the hope of speeding this process up), but depending on the display the refresh rate and amount of CPU time used may not give you the results you want.

Re: gpio display and hdmi display

Posted: Wed Apr 01, 2015 8:48 am
by brainbuddy
MarkHaysHarris777 wrote:
I got the raspberry pi b2 and I wanted to create a portable and main game station from it; so that I can play games on the bus and with a bigger screen home.
Really. Which screen are you going to use? How are you going to power it? Do you have a case for it already, or are you planning to print one on your 3D printer? What games do you plan to play on it?

Do you have an RPi 2, or do you have an RPi b+, or do you have an RPi 2B ?

Inquiring minds want to know.

(oh, almost forgot, it will be YOUR project; you tell the screens to do what YOU want them to do)
I got the raspberry pi b2 and I meanly want to use it for the mario kart 64 :)
I currentyl do not got an screen for it. I just use on of me monitor for me pi.
I do have a case I just use the case from a playing card deck cut some holes in it and taaadaaa you got an case ;)
AndyD wrote:The screens that plug into the GPIO provide a second framebuffer (if they are supported by the kernel module written by Notro and now available in the Raspbain kernel). So by default nothing it displayed on these GPIO displays.

Not everything displayed on the Raspberry Pi screen uses the framebuffer. Things like Minecraft and the GPU accelerated video player don't use the framebuffer and so can't (easily) be displayed on a GPIO display.

There is a program called fbcp that will copy everything on the Raspberry Pi display (I also wrote a similar program recently with the hope of speeding this process up), but depending on the display the refresh rate and amount of CPU time used may not give you the results you want.
okay so waht I understand what you say is that be default nothing is displayed when you put the adadruit diplay on it. in order to do this you need to write some code for it.
so is it also possible to prioritize the hdmi over the GPIO display ?

Re: gpio display and hdmi display

Posted: Wed Apr 01, 2015 8:56 am
by PiGraham
brainbuddy wrote:okay so waht I understand what you say is that be default nothing is displayed when you put the adadruit diplay on it. in order to do this you need to write some code for it.
so is it also possible to prioritize the hdmi over the GPIO display ?
No need for code. Run fbcp, as AndyD suggested, and whatever appears on the HDMI display is scaled and copied to the PiTFT. You may have to edit /boot/config.txt to get a suitable display mode when there is no HDMI connected, but it may just work.

Re: gpio display and hdmi display

Posted: Wed Apr 08, 2015 9:57 am
by givoanni-sciotti
Hi All!
i am new as well.
i have a similar question. In my project i would like to stream the camera module input with gstreamer and simultaneusly get a preview of the camera input on adafruit tft display part number 1983
Gstreamer is working incredibly piping raspivid to gst-launc command
Do you have ideas about how to get also the preview scaled on 320x240 display?
Thank you all for any info or link
Giovanni

Re: gpio display and hdmi display

Posted: Wed Apr 22, 2020 2:30 pm
by jateu01
I have a project where I am requiring everything to me on board and in cased. The video output is being powered by the gpio lcd. Here is the issue. I am using the pi cam to take pictures and I wish to use the lcd for preview. But when I run pi4 the lcd shows the os screen but it will not present the camera preview on lcd, regardless of scrips being run at start up of manually so. When I plug hdmi in the preview screen pops up there with a black screen and plenty of white text in bacround. Can any one point me in the right direction here

Many thanks

J

Re: gpio display and hdmi display

Posted: Sat May 02, 2020 6:06 am
by aBUGSworstnightmare
First of all you should start a new threat!
Second, have you connected two displays to your RPi and which GPIO LCD display do you use?
Third, your diplays needs to be connected at boot rime; you can't connect different displays on the fly.

Re: gpio display and hdmi display

Posted: Sat May 02, 2020 6:09 am
by Cory Parsnipson
brainbuddy wrote:
Wed Apr 01, 2015 8:48 am
so is it also possible to prioritize the hdmi over the GPIO display ?
If you're curious about switching between the two, there's apparently a thread where someone did that:
viewtopic.php?f=44&t=91764&start=75#p662735

Disclaimer: I haven't gotten around to reading it closely myself, but I'm planning on it in the next week or so.

This is more complicated than just mirroring both screens at the same time, in which case you should use fbcp like everyone else is saying.