I use DP on my Dev Kit board. I found DP can’t work in boot( I can’t see the boot logo when start) and there are errors in boot log. But when start kernel, DP works. I can see kernel boot logo and all display looks fine.
To enable DP in cboot, I add CONFIG_ENABLE_DP=1 in bootloader/partner/t18x/cboot/platform/t194/l4t.mk and build new cboot bin to flash into my board.
It is eDP on my board instead of DP. I also enabled CONFIG_ENABLE_EDP in mk file. But still not work. in boot.
From the boot log,
[0002.229] I> DP is connected
[0002.229] W> nvidia,lanes property not found
[0002.231] W> nvidia,link_bw property not found
[0002.236] W> dp lt-settings not read properly from dtb, we can still continue
[0002.243] E> cannot find any other nvdisp nodes
[0002.251] I> edid read success
[0002.251] I> width = 1920, height = 1200, frequency = 158000000
[0002.256] I> Best mode Width = 640, Height = 480, freq = 25174825
[0002.278] I> dp lt: CR done
[0002.280] I> dp lt: CE done
Below is the kernel log, DP works in kernel, I can see kernel logo on screen.
[ 1.920627] dp lt: state 5 (link training pass), pending_lt_evt 1
[ 1.920632] dp lt: switching from state 5 (link training pass) to state 0 (Reset)
[ 1.920637] dp lt: state 0 (Reset), pending_lt_evt 0
[ 1.920647] dp lt: link training force disable
[ 1.920651] dp lt: switching from state 0 (Reset) to state 4 (link training fail/disable)
[ 2.061740] dp lt: state 4 (link training fail/disable), pending_lt_evt 1
[ 2.061745] dp lt: switching from state 4 (link training fail/disable) to state 0 (Reset)
[ 2.061750] dp lt: state 0 (Reset), pending_lt_evt 0
[ 2.062799] max77620-power max20024-power: Event recorder REG_NVERC : 0x54
[ 2.063464] dp lt: switching from state 0 (Reset) to state 2 (clock recovery)
[ 2.063472] dp lt: state 2 (clock recovery), pending_lt_evt 0
[ 2.063997] dp lt: config: lane 0: vs level: 0, pe level: 0, pc2 level: 0
[ 2.064011] dp lt: config: lane 1: vs level: 0, pe level: 0, pc2 level: 0
[ 2.064020] dp lt: tx_pu: 0x20
[ 2.064958] dp lt: CR done
[ 2.064963] dp lt: switching from state 2 (clock recovery) to state 3 (channel equalization)
[ 2.064969] dp lt: state 3 (channel equalization), pending_lt_evt 0
[ 2.067111] dp lt: CE done
[ 2.067117] dp lt: switching from state 3 (channel equalization) to state 5 (link training pass)
This issue is related for DP to take long time to show the logo. I found if I wait more time on extlinux config ( TIMEOUT 70), I can see the boot logo display on screen.
I will open a new thread for DP take long time to show the picture.