kernel boot set display resolution

[Egor_I_InertgasM]

I have Variscite Symphony board on imx8mp SoM with LVDS panel and HDMI output.

I replaced psplash image. Image on the LVDS panel fits into panel resolution 800x480. And I do not use LVDS panel, I leave default settings from the vendor.

But the image on the HDMI panel 800x600 places into the top left corner.

I set HDMI resolution later in weston.ini.

But how can I set HDMI resolution at kernel boot or fit psplash image into HDMI display?

[Egor_I_InertgasM]

disabling LVDS panel in the device tree makes splashscreen on the HDMI panel better

[igorpadykov]

Hi Egor

i.MX8M Plus HDMI supports only CEA modes (800x600 is not CEA resolution) as described in

sect.13.9.1.2 Features  i.MX 8M Plus Applications Processor Reference Manual

"HDMI TX includes the following features:
• Compatible with HDMI v2.0a spec
• Decode/encode the following video modes:
• All 2D video formats described in the CEA-861-F specification up to 4Kp30."

Supported resolutions can be found in driver "struct *cea_mode"

https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/gpu/drm/drm_edid.c?h=lf-5.10.y

https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/video/fbdev/mxc/mxc_edid.c?h=lf-5....

Since hdmi driver is the same as for i.MX6Q:   https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/gpu/drm/imx/dw_hdmi-imx.c?h=lf-5.1...

one can try suggestions for i.MX6Q

https://community.nxp.com/t5/i-MX-Processors/iMX6Q-AI-board-support-for-1280-800-HDMI-Display/m-p/57...

Best regards
igor