Adding second frame buffer for iMX8 LVDS1

[tony-atlismv]

I would like to know how to setup a second frame buffer on the iMX8. I am using the imx8qm-mek with two different sized screens, where each screen is connected through a LVDS to HDMI converter. The first screen is connected to lvds0, and the second screen is connected to lvds1 of the im8qm mek. The problem is, there is only one frame buffer representing the two screens, /dev/fb0, where the second screen is extended from the first screen. I would like to have one screen with a frame buffer device node of /dev/fb0, and the other screen with a frame buffer device node of /dev/fb1 for example.

Looking through the imx8qm dts files, there is no alias referencing the frame buffer. I did see that the second LVDS Display Bridge (&ldb2) is setup with "lvds-channel@0" in the im8qm-mek.dts file. Although, changing it to "lvds-channel@1" just caused compiler errors. So, what do I need to change/modify in the dts files with the LVDS Display Bridge so the Linux kernel creates a second frame buffer for lvds1 on the imx8qm mek board? Linux kernel version is 5.4.70 (linux-imx).

Note, that I did find a NXP community reference article with a link on how to set up a custom screen, but this is for the iMX6 and the method has since been deprecated for the iMX8.

Any help would be greatly appreciated.

[tony-atlismv]

Weidong,

Thanks for the reply. I appologize, but I forgot that the iMX8 didn't support the frame buffer. Although, ironically, there is still a usable frame buffer that is created by the Linux kernel when executed on the iMX8QM MEK board. I will look to other sources as how to separate the two screens.

Thanks,

Tony S.

[PunitTeksun]

Hello Tony,

Did you find any solution? I am also facing the same issue

[weidong_sun · Accepted solution]

Hi Tony,

See i.MX_Yocto_Project_User's_Guide.pdf of L5.4.70_2.3.0, please!

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• fsl-imx-fb - Frame Buffer graphics - no X11 or Wayland. Frame Buffer is not supported on i.MX 8.

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Only i.MX6 & i.MX7 support Frame buffer.

Have a  nice day!

Regards,

weidong