arc19
Posts: 18
Joined: Mon Jul 08, 2019 1:59 pm

Disconnect RPi LCD Screen

Fri Jul 19, 2019 2:11 pm

Hi!
I've attached an RPi LCD Screen and am only getting the raspbian home page on my screen and not my monitor anymore (even though it is still connected). Does anyone know how I can get the screen back onto my monitor. I tried some things found on the internet but nothing seems to be working. If I take the Screen Off my monitor still stalls at the boot screen saying it found the device and is writing to that instead.

Thanks!
Last edited by arc19 on Fri Jul 19, 2019 2:24 pm, edited 1 time in total.

arc19
Posts: 18
Joined: Mon Jul 08, 2019 1:59 pm

Re: RPi LCD Screen

Fri Jul 19, 2019 2:23 pm

Just to clarify, I've tried HDMI-SYS-SHOW and omxplayer --display-=5

gkaiseril
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Re: Disconnect RPi LCD Screen

Fri Jul 19, 2019 2:38 pm

Raspberry Pis prior to Pi 4B could only drive one display. If the DSI connector has a connection all other monitors are disconnected. You need to remove the cable from the DSI port.
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W. H. Heydt
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Re: Disconnect RPi LCD Screen

Fri Jul 19, 2019 4:15 pm

gkaiseril wrote:
Fri Jul 19, 2019 2:38 pm
Raspberry Pis prior to Pi 4B could only drive one display. If the DSI connector has a connection all other monitors are disconnected. You need to remove the cable from the DSI port.
Wrong on two counts. First, there is a thread in General on beta testing concurrent use of fb0 and fb1, permitting two monitors to be used (but not, since the Pi4B has been released, three). Second, it is not necessary to disconnect the DSI cable to send video to an HDMI monitor. Just disconnect the power from the 7" display. That way, it won't be detected on boot up and will revert to the HDMI monitor.

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DougieLawson
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Re: Disconnect RPi LCD Screen

Sat Jul 20, 2019 7:32 am

W. H. Heydt wrote:
Fri Jul 19, 2019 4:15 pm
gkaiseril wrote:
Fri Jul 19, 2019 2:38 pm
Raspberry Pis prior to Pi 4B could only drive one display. If the DSI connector has a connection all other monitors are disconnected. You need to remove the cable from the DSI port.
Wrong on two counts. First, there is a thread in General on beta testing concurrent use of fb0 and fb1, permitting two monitors to be used (but not, since the Pi4B has been released, three). Second, it is not necessary to disconnect the DSI cable to send video to an HDMI monitor. Just disconnect the power from the 7" display. That way, it won't be detected on boot up and will revert to the HDMI monitor.
I was never able to get the DSI & HDMI stuff working with the alpha testing code (which is no-longer supported). Until you get a RPi4B it IS necessary to power down and disconnect power to the screen (which I do with a short USB-A to microUSB cable from the RPi3B+ to the screen). You have to reset the GPU with a power cycle to detect the HDMI.
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aBUGSworstnightmare
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Re: Disconnect RPi LCD Screen

Mon Jul 22, 2019 4:38 am

You may want to try this https://www.raspberrypi.org/forums/view ... 3&t=246384

RPi4 can only drive 2 displays, not 3.

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