IMX8QM-MEK HDMI LATENCY

[ekrem_sahin]

Hi,

I have an issue on imx8qm-mek reference platform which is related to showing linux clut224 logo that is defined by kernel config CONFIG_LOGO_LINUX_CLUT224. The logo becomes visible on hdmi after kernel boot-up is finished.

To give an example, Our optimized kernel boots up in 1.3 sec and linux logo is shown at 2.8th second on hdmi which is 1.5 second later from kernel boot-up.What I expect is to show the linux logo during kernel boot-up.

Also for test purposes I applied following changes:

1-Changed default mode from 3840x2160 to 1280x720 from imx-hdp.c file and it caused more and more delay on kernel  boot-up.

2-Disabled edid with fsl,no_edid from related dtsi file and configured bootargs from u-boot with "video=HDMI-A-1:1280x720" option but again it did not help to show linux logo earlier on kernel bootup.

Is there any idea what might be the cause of this or any suggestions for debugging the issue?

Regards

[Bio_TICFSL]

Hello Ekrem,

Which BSP are you using? you have to see which resolution is supported with $cat /sys/class/graphic/fb0/modes, also

check sect.Table 14. Known issues and workarounds for i.MX 8M of the Release Notes describes issues with some monitors, so one can try others.

Regards

[ekrem_sahin]

Hello,

Any feedback for the issue ?

Regards

[ekrem_sahin]

Hello,

Sorry for late answer, The bsp that I am using is Linux 4.14.98 yocto release and output of cat /sys/class/graphics/fb0/modes is: U:1280x720p-0.

I am using Lilliput monitor and I tried to check Table 14 but not sure what is my issue .So Can you tell me some debug points to address the issue for my current setup ?

Regards