Greetings Team,
I am trying to get the extended screen feature in imx8m som board using LVDS (primary screen) and HDMI (secondary/extended screen). But I am unable to achieve it.
Here are few inputs, describing the query in breif:
LVDS display [1280x800] is utilising frame buffer (/dev/fb1) and DRI card (/dev/dri/card1), where as
HDMI display [1920x1080] is utilising frame buffer (/dev/fb0) and DRI card (/dev/dri/card0)
Since both display's are reading data from different frame buffers & DRI cards (i.e., card0 and card1) we are unable to see the common output in both displays. Though We can run two different applications on both the displays at the same time. [PFA Snapshot, file name: dunfell_drm_card.png]
Same scenario I have checked on Ubuntu machine 20.04.4 LTS, by connecting HDMI display to my laptop. I found that my laptop display and HDMI display are pointing to same DRI card (i.e., card0), henceforth we are able to see common display on both screen as extended feature.[PFA Snapshot, file name: ubuntu_drm_card.png]
According to this analysis, I suspect that both displays should read data from one common frame buffer and DRI card. Let me know how this can be achieved
Thanks & Regards,
Mohammed Sadiq Afreed Meeran
