Have the 7" touchscreen display with Raspiberry pi 4. Fixed the upside display. Works great. Wondering if I can add a HDMI monitor. If so, how?
Have the 7" touchscreen display with Raspiberry pi 4. Fixed the upside display. Works great. Wondering if I can add a HDMI monitor. If so, how?
Hi,
I think that's not a supported combination, these were some comments I wrote a few years back - the situation may have changed, or it may not have changed:
I think there are some difficulties in doing this, there is some information in this thread How to run HDMI and Official Raspberry Pi Display (DSI) simultaneously?
According the raspberrypi.org link referenced off that, and also this link https://www.raspberrypi.org/forums/viewtopic.php?f=108&t=129211&p=880255 , only certain apps can do it, due to the fact that there is only one /dev/fb that gets created regardless if HDMI and the screen are present. So the situation seems stuck until someone with driver knowledge (and possibly GPU knowledge - not sure) can move things forward.
Hi,
I think that's not a supported combination, these were some comments I wrote a few years back - the situation may have changed, or it may not have changed:
I think there are some difficulties in doing this, there is some information in this thread How to run HDMI and Official Raspberry Pi Display (DSI) simultaneously?
According the raspberrypi.org link referenced off that, and also this link https://www.raspberrypi.org/forums/viewtopic.php?f=108&t=129211&p=880255 , only certain apps can do it, due to the fact that there is only one /dev/fb that gets created regardless if HDMI and the screen are present. So the situation seems stuck until someone with driver knowledge (and possibly GPU knowledge - not sure) can move things forward.
I haven't tried this myself, but according to a comment in this thread https://forums.raspberrypi.com/viewtopic.php?f=63&t=246384#p1504551
"The Pi4 does support HDMI0 + DSI out of the box, but not HDMI1 + DSI due to internal plumbing within the SoC. Please ensure you use the right HDMI connector."
I don't have a DSI LCD, so I can't try it. The link for the SPI display seems broken, but maybe I'll search for it if I want to try it in the future.